A275295 Number of set partitions of [2n] with symmetric block size list of length eight.

1, 70, 4005, 219521, 11954993, 653625597, 35989579051, 1997232863281, 111698425867139, 6292920483661649, 356957345427055439, 20375264103726231304, 1169732275950521805077, 67508137728429209948117, 3914904903283946200635048, 228039200549822180269793411

Offset

4,2

Links

Alois P. Heinz, Table of n, a(n) for n = 4..300

Wikipedia, Partition of a set

Formula

a(n) ~ 64^n / (20160*Pi^2*n^2). - Vaclav Kotesovec, Aug 02 2016

Example

a(4) = 1: 1|2|3|4|5|6|7|8.

Crossrefs

Bisection of column k=8 of A275281.

Sequence in context: A266739 A227273 A298463 * A306984 A292986 A064114

Adjacent sequences: A275292 A275293 A275294 * A275296 A275297 A275298

Keyword

nonn

Author

Alois P. Heinz, Jul 22 2016

Status

approved