A271752 Number of set partitions of [n+1] such that n is the largest element of the last block.
0, 1, 4, 15, 59, 250, 1145, 5649, 29874, 168509, 1009215, 6391484, 42648083, 298865333, 2193219124, 16811408659, 134289313167, 1115559002906, 9619253991637, 85950089855573, 794567157607386, 7588822028424393, 74783864494826723, 759461721024357540
Offset: 1
Keywords
Examples
a(3) = 4: 124|3, 14|23, 14|2|3, 1|24|3. a(4) = 15: 1235|4, 125|34, 125|3|4, 12|35|4, 135|24, 135|2|4, 13|25|4, 15|234, 15|23|4, 1|235|4, 15|2|34, 1|25|34, 15|2|3|4, 1|25|3|4, 1|2|35|4.
Links
- Alois P. Heinz, Table of n, a(n) for n = 1..576
- Wikipedia, Partition of a set
Crossrefs
A diagonal of A271466.
Formula
a(n) = A271466(n+1,n).