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.

A292744 a(0) = 1; a(n) = Sum_{k=1..n} prime(k+1)*a(n-k).

Original entry on oeis.org

1, 3, 14, 64, 294, 1346, 6166, 28242, 129362, 592538, 2714096, 12431808, 56943398, 260826950, 1194707382, 5472309246, 25065693008, 114812401444, 525893599720, 2408834540066, 11033569993066, 50538824799712, 231491059896394, 1060335514811206, 4856824295820082, 22246488881086116
Offset: 0

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Author

Ilya Gutkovskiy, Sep 22 2017

Keywords

Comments

Invert transform of the odd primes.
Number of compositions (ordered partitions) of n where there are prime(k+1) sorts of part k.

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[n_] := a[n] = Sum[Prime[k + 1] a[n - k], {k, 1, n}]; Table[a[n], {n, 0, 25}]
    nmax = 25; CoefficientList[Series[1/(1 - Sum[Prime[k + 1] x^k, {k, 1, nmax}]), {x, 0, nmax}], x]
  • PARI
    t=26; Vec(1/(1-sum(k=1, t, prime(k+1)*x^k)) + O(x^t)) \\ Felix Fröhlich, Sep 22 2017

Formula

G.f.: 1/(1 - Sum_{k>=1} prime(k+1)*x^k).