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.

A284171 Number of partitions of n into distinct perfect powers (including 1).

Original entry on oeis.org

1, 1, 0, 0, 1, 1, 0, 0, 1, 2, 1, 0, 1, 2, 1, 0, 1, 2, 1, 0, 1, 2, 1, 0, 1, 3, 2, 1, 2, 3, 2, 1, 2, 3, 3, 2, 4, 5, 3, 2, 4, 5, 3, 2, 4, 6, 4, 2, 4, 7, 5, 2, 5, 8, 5, 2, 5, 8, 6, 3, 5, 10, 8, 4, 6, 10, 8, 4, 6, 10, 9, 5, 7, 11, 10, 6, 8, 12, 10, 6, 8, 13, 11, 7, 9, 15, 13, 7, 10, 16, 14, 8, 10, 16, 15, 9, 10, 17, 16, 9, 11
Offset: 0

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Author

Ilya Gutkovskiy, Mar 21 2017

Keywords

Comments

Differs from the sequence A112345 which does not consider 1 as a perfect power.

Examples

			a(25) = 3 because we have [25], [16, 9] and [16, 8, 1].
		

Crossrefs

Programs

  • Mathematica
    nmax = 100; CoefficientList[Series[(1 + x) Product[(1 + Boole[GCD @@ FactorInteger[k][[All, 2]] > 1] x^k), {k, 1, nmax}], {x, 0, nmax}], x]
  • PARI
    Vec((1 + x) * prod(k=1, 100, 1 + (gcd(factorint(k)[,2])>1)*x^k) + O(x^101)) \\ Indranil Ghosh, Mar 21 2017

Formula

G.f.: Product_{k>=1} (1 + x^A001597(k)).
a(n) = A112345(n-1) + A112345(n).