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

0,3

Comments

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

Links

Alois P. Heinz, Table of n, a(n) for n = 0..200

Wikipedia, Partition of a set

Formula

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

Example

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.

Crossrefs

Cf. A271466.

Sequence in context: A213644 A280476 A295241 * A360481 A079244 A023815

Adjacent sequences: A271604 A271605 A271606 * A271608 A271609 A271610

Keyword

nonn

Author

Alois P. Heinz, Apr 10 2016

Status

approved