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.

A278929 Expansion of 1/(1 - Sum_{k>=1} x^(prime(k)^3)).

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 2, 0, 0, 0, 0, 1, 0, 0, 3, 0, 0, 0, 0, 1, 0, 0, 4, 0, 0, 1, 0, 1, 0, 0, 5, 0, 0, 3, 0, 1, 0, 0, 6, 0, 0, 6, 0, 1, 0, 0, 7, 0, 0, 10, 0, 1, 1, 0, 8, 0, 0, 15, 0, 1, 4, 0, 9, 0, 0, 21
Offset: 0

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Author

Ilya Gutkovskiy, Dec 24 2016

Keywords

Comments

Number of compositions (ordered partitions) of n into cubes of primes (A030078).

Examples

			a(35) = 2 because we have [8, 27] and [27, 8].
		

Crossrefs

Programs

  • Maple
    N:= 200:
    Primes:= select(isprime, [2,seq(i,i=3..floor(N^(1/3)),2)]):
    G:= 1/(1- add(x^(Primes[i]^3),i=1..nops(Primes))):
    S:= series(G,x,N+1):
    seq(coeff(S,x,j),j=0..N); # Robert Israel, Jan 23 2019
  • Mathematica
    nmax = 120; CoefficientList[Series[1/(1 - Sum[x^Prime[k]^3, {k, 1, nmax}]), {x, 0, nmax}], x]

Formula

G.f.: 1/(1 - Sum_{k>=1} x^(prime(k)^3)).