cp's OEIS Frontend

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.

A289080 a(0) = 1 and a(n) = A005169(n) - A005169(n-1).

Original entry on oeis.org

1, 0, 0, 1, 1, 2, 4, 6, 11, 19, 33, 57, 99, 172, 298, 518, 898, 1559, 2706, 4696, 8151, 14147, 24554, 42617, 73969, 128384, 222831, 386759, 671282, 1165118, 2022251, 3509944, 6092077, 10573790, 18352530, 31853801, 55287454, 95960372, 166554844, 289083043
Offset: 0

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Author

Seiichi Manyama, Sep 02 2017

Keywords

Crossrefs

Column 2 of A288267 (except a(0)).
Cf. A005169.

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0, 1,
          add(b(n-j, j), j=1..min(i+1, n)))
        end:
    a:= n-> b(n, 0) -b(n-1, 0):
    seq(a(n), n=0..50);  # Alois P. Heinz, Sep 02 2017
  • Mathematica
    b[n_, i_] := b[n, i] = If[n==0, 1, Sum[b[n-j, j], {j, 1, Min[i+1, n]}]];
    a[n_] := b[n, 0] - b[n-1, 0];
    a /@ Range[0, 50] (* Jean-François Alcover, Nov 14 2020, after Alois P. Heinz *)

Formula

G.f.: (1-x)/(1-x/(1-x^2/(1-x^3/(1-x^4/(1-x^5/(...)))))).