A271607 Number of set partitions of [2n+1] such that n+1 is the largest element of the last block.

1, 1, 6, 63, 1039, 24190, 745107, 29058813, 1389893708, 79588371929, 5353760622719, 416660175523064, 37047640989016445, 3724084616168887373, 419437505978046355690, 52523298180976612585435, 7263669823685446959438851, 1102849583101324096499809166

Offset: 0

Author

Alois P. Heinz, Apr 10 2016

Keywords

• nonn

Comments

Each set partition is written as a sequence of blocks, ordered by the smallest elements in the blocks.

Examples

			a(0) = 1: 1.
a(1) = 1: 13|2.
a(2) = 6: 1245|3, 145|23, 145|2|3, 14|25|3, 15|24|3, 1|245|3.
a(3) = 63: 123567|4, 12567|34, 12567|3|4, 1256|37|4, ..., 1|26|357|4, 17|2|356|4, 1|27|356|4, 1|2|3567|4.
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..200
• Wikipedia, Partition of a set

Crossrefs

Cf. A271466.

Formula

a(n) = A271466(2n+1,n+1).