A038042 Number of ways to partition a 2-colored labeled set into identical subsets.

2, 6, 10, 30, 34, 226, 130, 2078, 2754, 31770, 2050, 963826, 8194, 17320530, 45886578, 561051678, 131074, 29864241434, 524290, 759743216906, 4635692722434, 28158593662770, 8388610, 3930830007646194, 166229565054466

Offset

1,1

Links

Table of n, a(n) for n=1..25.

Formula

sum {d|n} ((2^d*n!)/(d!*((n/d)!)^d)).

Crossrefs

Sequence in context: A243393 A102581 A152000 * A032374 A342401 A074095

Adjacent sequences: A038039 A038040 A038041 * A038043 A038044 A038045

Keyword

nonn

Author

Christian G. Bower

Extensions

More terms from Michel ten Voorde Apr 13 2001

Status

approved