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This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

User: Mohamed Bensaid

Mohamed Bensaid's wiki page.

Mohamed Bensaid has authored 2 sequences.

A375922 a(n) = (a(n-3)*a(n-9) + a(n-1)*a(n-11))/a(n-12) with a(0) = ... = a(11) = 1.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 6, 9, 13, 19, 28, 41, 79, 163, 490, 972, 1785, 4270, 9483, 19251, 41603, 100739, 259579, 997371, 3297339, 12754875, 33992883, 94594611, 363844867, 1139238123, 3317604094, 12075672425, 56552033036, 254310500890
Offset: 0

Views

Author

Mohamed Bensaid, Sep 02 2024

Keywords

Comments

Sequence defined by recursion derived from Sato discrete tau function.
When extended to n<0 by a(n) = a(13-n) for all n in Z, then also a(n+6)*a(n-6) = a(n+5)*a(n-5) + a(n+3)*a(n-3) for all n in Z. It is a Gale-Robinson sequence. - Michael Somos, Nov 28 2024

Links

Crossrefs

Cf. A375621.

Programs

  • Maple
    a:= proc(n) option remember; `if`(n<12, 1,
     (a(n-3)*a(n-9)+a(n-1)*a(n-11))/a(n-12))
    end:
seq(a(n), n=0..42);  # Alois P. Heinz, Sep 02 2024
  • Mathematica
    a[n_] := a[n] = If[n < 12, 1, (a[n-3]*a[n-9] + a[n-1]*a[n-11]) / a[n-12]]; Array[a, 40, 0] (* Amiram Eldar, Sep 02 2024 *)
  • PARI
    seq(n)={my(a=vector(n+1,i,1)); for(n=13, #a, a[n] =(a[n-3]*a[n-9]+a[n-1]*a[n-11])/a[n-12]); a} \\ Andrew Howroyd, Sep 03 2024

A375621 a(n) = (a(n-3)*a(n-5) + a(n-1)*a(n-7))/a(n-8) with a(0) = ... = a(7) = 1.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 6, 9, 17, 35, 106, 210, 385, 1028, 2767, 9761, 32795, 129759, 351733, 1076957, 6165427, 27815973, 148629048, 721531991, 3768314574, 17276660082, 109959356649, 1149560654775, 7208229224331, 53412249630318, 392919259603556
Offset: 0

Views

Author

Mohamed Bensaid, Aug 21 2024

Keywords

Comments

Sequence defined by recursion derived from Sato discrete tau function.

Links

Crossrefs

Cf. A102276, A108896.

Programs

  • Maple
    a:= proc(n) option remember; `if`(n<8, 1,
     (a(n-3)*a(n-5) + a(n-1)*a(n-7))/a(n-8))
    end:
seq(a(n), n=0..35);  # Alois P. Heinz, Aug 24 2024
  • Python
    def calculate_terms(n):
    a = [1] * n
    for l in range(n - 8):
        a[l + 8] = (a[l + 3] * a[l + 5] + a[l + 7] * a[l + 1]) // a[l]
    return a

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