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.

A241864 Number of compositions of n such that the smallest part has multiplicity four.

Original entry on oeis.org

1, 0, 5, 5, 21, 35, 85, 175, 366, 730, 1481, 2925, 5726, 11110, 21375, 40766, 77266, 145495, 272290, 506836, 938783, 1730725, 3176920, 5808020, 10578162, 19197898, 34725765, 62616485, 112574807, 201827366, 360885835, 643679795, 1145341756, 2033369086
Offset: 4

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Author

Joerg Arndt and Alois P. Heinz, Apr 30 2014

Keywords

Crossrefs

Column k=4 of A238342.

Programs

  • Maple
    b:= proc(n, s) option remember; `if`(n=0, 1,
          `if`(nadd(coeff(p, x, i)*binomial(i+k, k),
           i=0..degree(p)))(b(n-j*k, j+1)), j=1..n/k)
        end:
    seq(a(n), n=4..40);
  • Mathematica
    b[n_, s_] := b[n, s] = If[n == 0, 1, If[nJean-François Alcover, Feb 09 2015, after Maple *)

Formula

a(n) ~ (1/2-1/sqrt(5))^3 / 15 * n^4 * ((1+sqrt(5))/2)^n. - Vaclav Kotesovec, May 01 2014