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

Author

Alois P. Heinz, Jul 22 2016

Keywords

• nonn

Examples

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

Links

• Alois P. Heinz, Table of n, a(n) for n = 4..300
• Wikipedia, Partition of a set

Crossrefs

Bisection of column k=8 of A275281.

Formula

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