A261961 - cp's OEIS frontend

A261961 Number of ordered set partitions of {1,2,...,n} such that no part has the same size as any of its two immediate predecessors.

n	a(n)
0	1
1	1
2	1
3	7
4	9
5	31
6	403
7	1597
8	7913
9	68551
10	539691
11	4359037
12	48419715
13	560648557
14	4985097601
15	59798395027
16	869794249513
17	11143895125527
18	159575614945315
19	2593765421983597
20	38615447492264219
21	642012651525487501
22	11768461266053785921
23	220201814964135821967

[1, 1, 1, 7, 9, 31, 403, 1597, 7913, 68551, 539691, 4359037, 48419715, 560648557, 4985097601, 59798395027, 869794249513, 11143895125527, 159575614945315, 2593765421983597, 38615447492264219, 642012651525487501, 11768461266053785921, 220201814964135821967]

cp's OEIS Frontend

A261961 Number of ordered set partitions of {1,2,...,n} such that no part has the same size as any of its two immediate predecessors.

Table of values

List of values