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.

A104648 Cardinality of set of sets of parts of all partitions of n into odd parts.

Original entry on oeis.org

1, 1, 1, 2, 2, 3, 4, 4, 5, 7, 8, 9, 11, 13, 15, 18, 20, 24, 28, 31, 36, 41, 47, 52, 60, 68, 76, 86, 96, 108, 121, 134, 150, 168, 185, 204, 228, 254, 279, 308, 339, 377, 411, 453, 496, 541, 597, 653, 713, 782, 851, 928, 1013, 1105, 1200, 1299, 1420, 1540, 1674, 1812, 1960
Offset: 0

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Author

Vladeta Jovovic, Apr 21 2005

Keywords

Examples

			a(7) = |{{1}, {7}, {1, 3}, {1, 5}}| = 4.
		

Crossrefs

Cf. A088314.

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0, {{}}, `if`(i<1, {},
          {b(n, i-2)[], `if`(i>n, [][], map(x-> {x[], i}, b(n-i, i))[])}))
        end:
    a:= n-> nops(b(n, n-1+irem(n, 2))):
    seq(a(n), n=0..60);  # Alois P. Heinz, Jun 30 2016
  • Mathematica
    a[n_] := Union /@ IntegerPartitions[n, All, Range[1, n, 2]] // Union // Length;
    a /@ Range[0, 60] (* Jean-François Alcover, Nov 18 2020 *)

Extensions

More terms from David Wasserman, Apr 24 2008
a(0)=1 from Alois P. Heinz, Jun 30 2016