A275781 Number of set partitions of [n] having at least two blocks with equal element sums.

0, 0, 0, 1, 3, 9, 43, 209, 1042, 5682, 32875, 200919, 1299092, 8848623, 63108778, 471509591, 3671980053, 29797471739, 251120234182, 2196428139810, 19882638695048, 186205573812059, 1799766634300161, 17946783669353462, 184277407872729741, 1947501874827169041

Offset

0,5

Links

Table of n, a(n) for n=0..25.

Formula

a(n) = A000110(n) - A275780(n).

Example

a(3) = 1: 12|3
a(4) = 3: 12|3|4, 13|2|4, 14|23.
a(5) = 9: 12|3|45, 12|3|4|5, 13|25|4, 13|2|4|5, 14|23|5, 1|23|4|5, 14|2|3|5, 15|24|3, 1|25|34.

Crossrefs

Cf. A000110, A035470, A275780.

Sequence in context: A141349 A018427 A377062 * A199140 A154606 A369387

Adjacent sequences: A275778 A275779 A275780 * A275782 A275783 A275784

Keyword

nonn

Author

Alois P. Heinz, Aug 08 2016

Extensions

a(17)-a(25) from Christian Sievers, Aug 20 2024

Status

approved