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.

A239509 Number of partitions of n into distinct nonprime squarefree numbers, cf. A000469.

Original entry on oeis.org

1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 3, 3, 1, 1, 2, 2, 2, 2, 2, 3, 4, 4, 3, 2, 4, 7, 6, 4, 5, 6, 6, 7, 7, 6, 8, 10, 9, 9, 10, 10, 12, 13, 12, 13, 15, 16, 18, 18, 16, 17, 21, 23, 23, 23, 25, 28, 29, 29, 31, 34, 37, 41, 40, 38, 42, 46
Offset: 0

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Author

Reinhard Zumkeller, Mar 21 2014

Keywords

Examples

			a(30) = #{30, 15+14+1, 14+10+6} = 3;
a(31) = #{30+1, 21+10, 15+10+6, 14+10+6+1} = 4;
a(32) = #{26+6, 22+10, 21+10+1, 15+10+6+1} = 4;
a(33) = #{33, 26+6+1, 22+10+1} = 3;
a(34) = #{34, 33+1} = 2;
a(35) = #{35, 34+1, 21+14, 15+14+6} = 4;
a(36) = #{35+1, 30+6, 26+10, 22+14, 21+15, 21+14+1, 15+14+6+1} = 7.
		

Crossrefs

Programs

  • Haskell
    a239509 = p a000469_list where
       p _      0 = 1
       p (k:ks) m = if m < k then 0 else p ks (m - k) + p ks m
  • Maple
    b:= proc(n, i) option remember; `if`(i*(i+1)/2 b(n$2):
    seq(a(n), n=0..100);  # Alois P. Heinz, Jun 02 2015
  • Mathematica
    b[n_, i_] := b[n, i] = If[i*(i+1)/2Jean-François Alcover, Jan 15 2016, after Alois P. Heinz *)