Why is the 0th term of the padovan sequence 1 but for fibonacci it is 0?












1














padovan numbers are:



P(0)=1, P(1)=1, P(2)=1, P(3)=2, P(4)=2, P(5)=3, 4, 5, 7, 9, 12, 16, 21, etc



WHERE P(n) = P(n-2) + P(n-3)



fibonacci numbers are:



F(0)=0, F(1)=1, F(2)=1, F(3)=2, F(4)=3, F(5)=5, 8, 13, 21, etc



WHERE F(n) = F(n-1) + F(n-2)



Question



My question is, why not use P(0)=0 as follows:



P(0)=0, P(1)=1, P(2)=1, P(3)=1, P(4)=2, P(5)=2, P(6)=3, 4, 5, 7, 9, 12, 16, 21, etc



Since this satisfies P(n) = P(n-2) + P(n-3)



Also, when looking at the Fibonacci squares we see the first visible term of the sequence is F(1)



enter image description here



With the Padovan triangles the first visible term of the sequence is P(0)?



enter image description here



Which seems inconsistent to me. Can anyone give a mathematical explanation as to why P(0)=1 ... many thanks










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    1














    padovan numbers are:



    P(0)=1, P(1)=1, P(2)=1, P(3)=2, P(4)=2, P(5)=3, 4, 5, 7, 9, 12, 16, 21, etc



    WHERE P(n) = P(n-2) + P(n-3)



    fibonacci numbers are:



    F(0)=0, F(1)=1, F(2)=1, F(3)=2, F(4)=3, F(5)=5, 8, 13, 21, etc



    WHERE F(n) = F(n-1) + F(n-2)



    Question



    My question is, why not use P(0)=0 as follows:



    P(0)=0, P(1)=1, P(2)=1, P(3)=1, P(4)=2, P(5)=2, P(6)=3, 4, 5, 7, 9, 12, 16, 21, etc



    Since this satisfies P(n) = P(n-2) + P(n-3)



    Also, when looking at the Fibonacci squares we see the first visible term of the sequence is F(1)



    enter image description here



    With the Padovan triangles the first visible term of the sequence is P(0)?



    enter image description here



    Which seems inconsistent to me. Can anyone give a mathematical explanation as to why P(0)=1 ... many thanks










    share|cite|improve this question







    New contributor




    danday74 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.























      1












      1








      1







      padovan numbers are:



      P(0)=1, P(1)=1, P(2)=1, P(3)=2, P(4)=2, P(5)=3, 4, 5, 7, 9, 12, 16, 21, etc



      WHERE P(n) = P(n-2) + P(n-3)



      fibonacci numbers are:



      F(0)=0, F(1)=1, F(2)=1, F(3)=2, F(4)=3, F(5)=5, 8, 13, 21, etc



      WHERE F(n) = F(n-1) + F(n-2)



      Question



      My question is, why not use P(0)=0 as follows:



      P(0)=0, P(1)=1, P(2)=1, P(3)=1, P(4)=2, P(5)=2, P(6)=3, 4, 5, 7, 9, 12, 16, 21, etc



      Since this satisfies P(n) = P(n-2) + P(n-3)



      Also, when looking at the Fibonacci squares we see the first visible term of the sequence is F(1)



      enter image description here



      With the Padovan triangles the first visible term of the sequence is P(0)?



      enter image description here



      Which seems inconsistent to me. Can anyone give a mathematical explanation as to why P(0)=1 ... many thanks










      share|cite|improve this question







      New contributor




      danday74 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.











      padovan numbers are:



      P(0)=1, P(1)=1, P(2)=1, P(3)=2, P(4)=2, P(5)=3, 4, 5, 7, 9, 12, 16, 21, etc



      WHERE P(n) = P(n-2) + P(n-3)



      fibonacci numbers are:



      F(0)=0, F(1)=1, F(2)=1, F(3)=2, F(4)=3, F(5)=5, 8, 13, 21, etc



      WHERE F(n) = F(n-1) + F(n-2)



      Question



      My question is, why not use P(0)=0 as follows:



      P(0)=0, P(1)=1, P(2)=1, P(3)=1, P(4)=2, P(5)=2, P(6)=3, 4, 5, 7, 9, 12, 16, 21, etc



      Since this satisfies P(n) = P(n-2) + P(n-3)



      Also, when looking at the Fibonacci squares we see the first visible term of the sequence is F(1)



      enter image description here



      With the Padovan triangles the first visible term of the sequence is P(0)?



      enter image description here



      Which seems inconsistent to me. Can anyone give a mathematical explanation as to why P(0)=1 ... many thanks







      sequences-and-series fibonacci-numbers






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      asked 1 hour ago









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          2 Answers
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          3














          The OEIS sequence A000931 is "Padovan sequence (or Padovan numbers): a(n) = a(n-2) + a(n-3) with a(0)=1, a(1)=a(2)=0." In contrast, your sequence $P(n) = A000931(n+5) = A134816(n+1).$ The OEIS entry also states




          The following are basically all variants of the same sequence: A000931, A078027, A096231, A124745, A133034, A134816, A164001, A182097, A228361 and probably A020720. However, each one has its own special features and deserves its own entry.




          The point is that it is a matter of convenience and choice of where to start the sequence and what index to use. The same holds for the Fibonacci numbers. Some people choose $F(0)=F(1)=1$. About your specific choice of $P(0)=P(1)=P(2)=1,$ that is exactly A134816 except offset differs by 1. You are welcome to submit your different offset sequence to the OEIS, but unlikely to succeed.






          share|cite|improve this answer































            2














            Recurrence relations like those allow for going backwards; for instance we can define $F(-1)$ by $F(1)=F(0)+F(-1)$, so
            $$
            F(-1)=F(1)-F(0)=1
            $$

            Similarly, $F(-2)=F(0)-F(-1)=-1$ and so on. If we translate indices, we get a new Fibonacci-like sequence
            $$
            F'(0)=1,quad F'(1)=0,quad F'(n+2)=F'(n+1)+F'(n)
            $$

            and another one if we start from $-2$ and translate indices by $2$:
            $$
            F''(0)=-1,quad F'(1)=1,quad F''(n+2)=F''(n+1)+F''(n)
            $$



            If we apply the same idea to the Padovan sequence, we need $P(2)=P(0)+P(-1)$, so $P(-1)=P(2)-P(0)=0$ and we could define
            $$
            P'(0)=0,quad P'(1)=1,quad P'(2)=1,quad P'(n+3)=P'(n+1)+P'(n)
            $$

            Nothing different and no real mathematical explanation. Just history.






            share|cite|improve this answer





















            • Note that F(-n) = (-1)^n * F(n) when n>=0, which makes the choice F(0) = 0 more natural, as it makes the sequence symmetrical (apart from the sign).
              – Sjoerd
              3 mins ago













            Your Answer





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            2 Answers
            2






            active

            oldest

            votes








            2 Answers
            2






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            3














            The OEIS sequence A000931 is "Padovan sequence (or Padovan numbers): a(n) = a(n-2) + a(n-3) with a(0)=1, a(1)=a(2)=0." In contrast, your sequence $P(n) = A000931(n+5) = A134816(n+1).$ The OEIS entry also states




            The following are basically all variants of the same sequence: A000931, A078027, A096231, A124745, A133034, A134816, A164001, A182097, A228361 and probably A020720. However, each one has its own special features and deserves its own entry.




            The point is that it is a matter of convenience and choice of where to start the sequence and what index to use. The same holds for the Fibonacci numbers. Some people choose $F(0)=F(1)=1$. About your specific choice of $P(0)=P(1)=P(2)=1,$ that is exactly A134816 except offset differs by 1. You are welcome to submit your different offset sequence to the OEIS, but unlikely to succeed.






            share|cite|improve this answer




























              3














              The OEIS sequence A000931 is "Padovan sequence (or Padovan numbers): a(n) = a(n-2) + a(n-3) with a(0)=1, a(1)=a(2)=0." In contrast, your sequence $P(n) = A000931(n+5) = A134816(n+1).$ The OEIS entry also states




              The following are basically all variants of the same sequence: A000931, A078027, A096231, A124745, A133034, A134816, A164001, A182097, A228361 and probably A020720. However, each one has its own special features and deserves its own entry.




              The point is that it is a matter of convenience and choice of where to start the sequence and what index to use. The same holds for the Fibonacci numbers. Some people choose $F(0)=F(1)=1$. About your specific choice of $P(0)=P(1)=P(2)=1,$ that is exactly A134816 except offset differs by 1. You are welcome to submit your different offset sequence to the OEIS, but unlikely to succeed.






              share|cite|improve this answer


























                3












                3








                3






                The OEIS sequence A000931 is "Padovan sequence (or Padovan numbers): a(n) = a(n-2) + a(n-3) with a(0)=1, a(1)=a(2)=0." In contrast, your sequence $P(n) = A000931(n+5) = A134816(n+1).$ The OEIS entry also states




                The following are basically all variants of the same sequence: A000931, A078027, A096231, A124745, A133034, A134816, A164001, A182097, A228361 and probably A020720. However, each one has its own special features and deserves its own entry.




                The point is that it is a matter of convenience and choice of where to start the sequence and what index to use. The same holds for the Fibonacci numbers. Some people choose $F(0)=F(1)=1$. About your specific choice of $P(0)=P(1)=P(2)=1,$ that is exactly A134816 except offset differs by 1. You are welcome to submit your different offset sequence to the OEIS, but unlikely to succeed.






                share|cite|improve this answer














                The OEIS sequence A000931 is "Padovan sequence (or Padovan numbers): a(n) = a(n-2) + a(n-3) with a(0)=1, a(1)=a(2)=0." In contrast, your sequence $P(n) = A000931(n+5) = A134816(n+1).$ The OEIS entry also states




                The following are basically all variants of the same sequence: A000931, A078027, A096231, A124745, A133034, A134816, A164001, A182097, A228361 and probably A020720. However, each one has its own special features and deserves its own entry.




                The point is that it is a matter of convenience and choice of where to start the sequence and what index to use. The same holds for the Fibonacci numbers. Some people choose $F(0)=F(1)=1$. About your specific choice of $P(0)=P(1)=P(2)=1,$ that is exactly A134816 except offset differs by 1. You are welcome to submit your different offset sequence to the OEIS, but unlikely to succeed.







                share|cite|improve this answer














                share|cite|improve this answer



                share|cite|improve this answer








                edited 38 mins ago

























                answered 1 hour ago









                Somos

                12.9k11034




                12.9k11034























                    2














                    Recurrence relations like those allow for going backwards; for instance we can define $F(-1)$ by $F(1)=F(0)+F(-1)$, so
                    $$
                    F(-1)=F(1)-F(0)=1
                    $$

                    Similarly, $F(-2)=F(0)-F(-1)=-1$ and so on. If we translate indices, we get a new Fibonacci-like sequence
                    $$
                    F'(0)=1,quad F'(1)=0,quad F'(n+2)=F'(n+1)+F'(n)
                    $$

                    and another one if we start from $-2$ and translate indices by $2$:
                    $$
                    F''(0)=-1,quad F'(1)=1,quad F''(n+2)=F''(n+1)+F''(n)
                    $$



                    If we apply the same idea to the Padovan sequence, we need $P(2)=P(0)+P(-1)$, so $P(-1)=P(2)-P(0)=0$ and we could define
                    $$
                    P'(0)=0,quad P'(1)=1,quad P'(2)=1,quad P'(n+3)=P'(n+1)+P'(n)
                    $$

                    Nothing different and no real mathematical explanation. Just history.






                    share|cite|improve this answer





















                    • Note that F(-n) = (-1)^n * F(n) when n>=0, which makes the choice F(0) = 0 more natural, as it makes the sequence symmetrical (apart from the sign).
                      – Sjoerd
                      3 mins ago


















                    2














                    Recurrence relations like those allow for going backwards; for instance we can define $F(-1)$ by $F(1)=F(0)+F(-1)$, so
                    $$
                    F(-1)=F(1)-F(0)=1
                    $$

                    Similarly, $F(-2)=F(0)-F(-1)=-1$ and so on. If we translate indices, we get a new Fibonacci-like sequence
                    $$
                    F'(0)=1,quad F'(1)=0,quad F'(n+2)=F'(n+1)+F'(n)
                    $$

                    and another one if we start from $-2$ and translate indices by $2$:
                    $$
                    F''(0)=-1,quad F'(1)=1,quad F''(n+2)=F''(n+1)+F''(n)
                    $$



                    If we apply the same idea to the Padovan sequence, we need $P(2)=P(0)+P(-1)$, so $P(-1)=P(2)-P(0)=0$ and we could define
                    $$
                    P'(0)=0,quad P'(1)=1,quad P'(2)=1,quad P'(n+3)=P'(n+1)+P'(n)
                    $$

                    Nothing different and no real mathematical explanation. Just history.






                    share|cite|improve this answer





















                    • Note that F(-n) = (-1)^n * F(n) when n>=0, which makes the choice F(0) = 0 more natural, as it makes the sequence symmetrical (apart from the sign).
                      – Sjoerd
                      3 mins ago
















                    2












                    2








                    2






                    Recurrence relations like those allow for going backwards; for instance we can define $F(-1)$ by $F(1)=F(0)+F(-1)$, so
                    $$
                    F(-1)=F(1)-F(0)=1
                    $$

                    Similarly, $F(-2)=F(0)-F(-1)=-1$ and so on. If we translate indices, we get a new Fibonacci-like sequence
                    $$
                    F'(0)=1,quad F'(1)=0,quad F'(n+2)=F'(n+1)+F'(n)
                    $$

                    and another one if we start from $-2$ and translate indices by $2$:
                    $$
                    F''(0)=-1,quad F'(1)=1,quad F''(n+2)=F''(n+1)+F''(n)
                    $$



                    If we apply the same idea to the Padovan sequence, we need $P(2)=P(0)+P(-1)$, so $P(-1)=P(2)-P(0)=0$ and we could define
                    $$
                    P'(0)=0,quad P'(1)=1,quad P'(2)=1,quad P'(n+3)=P'(n+1)+P'(n)
                    $$

                    Nothing different and no real mathematical explanation. Just history.






                    share|cite|improve this answer












                    Recurrence relations like those allow for going backwards; for instance we can define $F(-1)$ by $F(1)=F(0)+F(-1)$, so
                    $$
                    F(-1)=F(1)-F(0)=1
                    $$

                    Similarly, $F(-2)=F(0)-F(-1)=-1$ and so on. If we translate indices, we get a new Fibonacci-like sequence
                    $$
                    F'(0)=1,quad F'(1)=0,quad F'(n+2)=F'(n+1)+F'(n)
                    $$

                    and another one if we start from $-2$ and translate indices by $2$:
                    $$
                    F''(0)=-1,quad F'(1)=1,quad F''(n+2)=F''(n+1)+F''(n)
                    $$



                    If we apply the same idea to the Padovan sequence, we need $P(2)=P(0)+P(-1)$, so $P(-1)=P(2)-P(0)=0$ and we could define
                    $$
                    P'(0)=0,quad P'(1)=1,quad P'(2)=1,quad P'(n+3)=P'(n+1)+P'(n)
                    $$

                    Nothing different and no real mathematical explanation. Just history.







                    share|cite|improve this answer












                    share|cite|improve this answer



                    share|cite|improve this answer










                    answered 1 hour ago









                    egreg

                    178k1484201




                    178k1484201












                    • Note that F(-n) = (-1)^n * F(n) when n>=0, which makes the choice F(0) = 0 more natural, as it makes the sequence symmetrical (apart from the sign).
                      – Sjoerd
                      3 mins ago




















                    • Note that F(-n) = (-1)^n * F(n) when n>=0, which makes the choice F(0) = 0 more natural, as it makes the sequence symmetrical (apart from the sign).
                      – Sjoerd
                      3 mins ago


















                    Note that F(-n) = (-1)^n * F(n) when n>=0, which makes the choice F(0) = 0 more natural, as it makes the sequence symmetrical (apart from the sign).
                    – Sjoerd
                    3 mins ago






                    Note that F(-n) = (-1)^n * F(n) when n>=0, which makes the choice F(0) = 0 more natural, as it makes the sequence symmetrical (apart from the sign).
                    – Sjoerd
                    3 mins ago












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