Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #5 Apr 11 2016 09:05:14
%S 1,1,6,63,1039,24190,745107,29058813,1389893708,79588371929,
%T 5353760622719,416660175523064,37047640989016445,3724084616168887373,
%U 419437505978046355690,52523298180976612585435,7263669823685446959438851,1102849583101324096499809166
%N Number of set partitions of [2n+1] such that n+1 is the largest element of the last block.
%C Each set partition is written as a sequence of blocks, ordered by the smallest elements in the blocks.
%H Alois P. Heinz, <a href="/A271607/b271607.txt">Table of n, a(n) for n = 0..200</a>
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Partition_of_a_set">Partition of a set</a>
%F a(n) = A271466(2n+1,n+1).
%e a(0) = 1: 1.
%e a(1) = 1: 13|2.
%e a(2) = 6: 1245|3, 145|23, 145|2|3, 14|25|3, 15|24|3, 1|245|3.
%e 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.
%Y Cf. A271466.
%K nonn
%O 0,3
%A _Alois P. Heinz_, Apr 10 2016