A275294 Number of set partitions of [2n] with symmetric block size list of length six.

1, 34, 1035, 31346, 958708, 29677572, 929442097, 29416786597, 939795181248, 30273240306244, 982317847204631, 32081167538512119, 1053762976292882820, 34790825470327029730, 1153951843926244071285, 38433994194836318210579, 1284926817226752232868308

Offset

3,2

Links

Alois P. Heinz, Table of n, a(n) for n = 3..300

Vaclav Kotesovec, Recurrence (of order 5)

Wikipedia, Partition of a set

Formula

a(n) ~ 2^(2*n - 6) * 3^(2*n - 1/2) / (5*Pi^(3/2)*n^(3/2)). - Vaclav Kotesovec, Aug 02 2016

Example

a(3) = 1: 1|2|3|4|5|6.
a(4) = 34: 12|3|4|5|6|78, 13|2|4|5|6|78, 1|23|4|5|67|8, 1|23|4|5|68|7, 14|2|3|5|6|78, 1|24|3|5|67|8, 1|24|3|5|68|7, 1|2|34|56|7|8, 1|2|34|57|6|8, 1|2|34|58|6|7, 15|2|3|4|6|78, 1|25|3|4|67|8, 1|25|3|4|68|7, 1|2|35|46|7|8, 1|2|35|47|6|8, 1|2|35|48|6|7, 1|2|36|45|7|8, 1|2|37|45|6|8, 1|2|38|45|6|7, 16|2|3|4|5|78, 1|26|3|4|57|8, 1|26|3|4|58|7, 1|2|36|47|5|8, 1|2|36|48|5|7, 1|2|37|46|5|8, 1|2|38|46|5|7, 1|27|3|4|56|8, 1|28|3|4|56|7, 17|2|3|4|5|68, 1|27|3|4|58|6, 1|2|37|48|5|6, 1|2|38|47|5|6, 1|28|3|4|57|6, 18|2|3|4|5|67.

Crossrefs

Bisection of column k=6 of A275281.

Sequence in context: A297456 A328350 A365993 * A296724 A214190 A214241

Adjacent sequences: A275291 A275292 A275293 * A275295 A275296 A275297

Keyword

nonn

Author

Alois P. Heinz, Jul 22 2016

Status

approved