A272431 Number of ordered set partitions of {1,2,...,n} such that no part has the same size as any of its three immediate predecessors.

1, 1, 1, 7, 9, 31, 403, 757, 2873, 12607, 333051, 1592977, 10684875, 105031681, 697538325, 8987362027, 114294624633, 975751249951, 14157072527947, 124133073947209, 2048876740991939, 36859613739949357, 443133109281574185, 6166869485798451019

Offset: 0

Author

Alois P. Heinz, Apr 29 2016

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..100

Crossrefs

Column k=3 of A261959.