A275073 Number of set partitions of [n] such that i-j is a multiple of six for all i,j belonging to the same block.
1, 1, 1, 1, 1, 1, 1, 2, 4, 8, 16, 32, 64, 160, 400, 1000, 2500, 6250, 15625, 46875, 140625, 421875, 1265625, 3796875, 11390625, 39487500, 136890000, 474552000, 1645113600, 5703060480, 19770609664, 77181418496, 301304383744, 1176245959616, 4591883265424
Offset: 0
Keywords
Examples
a(9) = 8: 17|28|39|4|5|6, 17|28|3|4|5|6|9, 17|2|39|4|5|6|8, 17|2|3|4|5|6|8|9, 1|28|39|4|5|6|7, 1|28|3|4|5|6|7|9, 1|2|39|4|5|6|7|8, 1|2|3|4|5|6|7|8|9.
Links
- Alois P. Heinz, Table of n, a(n) for n = 0..801
- Wikipedia, Partition of a set
Formula
a(n) = Product_{i=0..5} A000110(floor((n+i)/6)).