A241723 Number of compositions of n into distinct parts with exactly four descents.
1, 1, 2, 3, 5, 7, 67, 70, 132, 194, 315, 436, 674, 2046, 2401, 3948, 5669, 8582, 11784, 17312, 23187, 47121, 56974, 86078, 116892, 169282, 223496, 316211, 413133, 565423, 879530, 1111950, 1523112, 2042569, 2744398, 3588200, 4804470, 6199849, 8142059, 10485846
Offset: 15
Keywords
Examples
a(20) = 7: [7,6,4,2,1], [8,5,4,2,1], [10,4,3,2,1], [8,6,3,2,1], [9,5,3,2,1], [6,5,4,3,2], [7,5,4,3,1].
Links
- Alois P. Heinz, Table of n, a(n) for n = 15..1000
Crossrefs
Column k=4 of A241719.