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.

A078635 Number of partitions of n into perfect powers.

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 2, 2, 4, 5, 5, 5, 7, 8, 8, 8, 12, 14, 15, 15, 19, 21, 22, 22, 28, 33, 35, 37, 43, 48, 50, 52, 62, 70, 75, 79, 92, 100, 105, 109, 126, 140, 148, 157, 177, 194, 202, 211, 237, 261, 276, 290, 324, 351, 370, 384, 424, 462, 489, 514, 562, 609, 640, 670, 728
Offset: 0

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Author

Henry Bottomley, Dec 12 2002

Keywords

Examples

			a(10)=5 since 10 can be written as 9+1, 8+1+1, 4+4+1+1, 4+1+1+1+1+1+1, or 1+1+1+1+1+1+1+1+1+1.
		

Crossrefs

Cf. A001597.
Cf. A131799.

Programs

  • Mathematica
    t = Union[Flatten[Table[n^k, {n, 1, 60}, {k, 2, 10}]]]; p[n_] := IntegerPartitions[n, All, t]; Table[p[n], {n, 0, 12}] (*shows partitions*)
    a[n_] := Length@p@n; a /@ Range[0, 80]
    (* Clark Kimberling, Mar 09 2014 *)
    With[{nn = 64}, CoefficientList[Series[Product[1/(1 - x^k), {k, Select[Range[nn], # == 1 || GCD @@ FactorInteger[#][[All, -1]] > 1 &]}], {x, 0, nn}], x]] (* Michael De Vlieger, Sep 06 2022 *)

Formula

G.f.: Product_{k=i^j, i>=1, j>=2, excluding duplicates} 1/(1 - x^k). - Ilya Gutkovskiy, Mar 21 2017