A241720 Number of compositions of n into distinct parts with exactly one descent.

1, 1, 2, 6, 7, 11, 16, 31, 36, 55, 71, 101, 147, 188, 245, 327, 421, 540, 732, 899, 1154, 1445, 1831, 2253, 2846, 3545, 4352, 5352, 6576, 7993, 9778, 11826, 14314, 17430, 20866, 25076, 30043, 35974, 42776, 51053, 60463, 71772, 85094, 100370, 118155, 139331

Offset

3,3

Links

Alois P. Heinz, Table of n, a(n) for n = 3..1000

Example

a(3) = 1: [2,1].
a(4) = 1: [3,1].
a(5) = 2: [3,2], [4,1].
a(6) = 6: [4,2], [5,1], [2,3,1], [3,1,2], [1,3,2], [2,1,3].
a(7) = 7: [4,3], [5,2], [6,1], [2,4,1], [4,1,2], [1,4,2], [2,1,4].
a(8) = 11: [6,2], [5,3], [7,1], [1,4,3], [3,1,4], [2,1,5], [3,4,1], [2,5,1], [5,1,2], [1,5,2], [4,1,3].
a(9) = 16: [5,4], [8,1], [7,2], [6,3], [2,6,1], [3,5,1], [6,1,2], [1,6,2], [2,1,6], [3,4,2], [4,2,3], [5,1,3], [2,4,3], [1,5,3], [3,2,4], [3,1,5].

Crossrefs

Column k=1 of A241719.

Sequence in context: A088227 A231500 A174000 * A224082 A051678 A079906

Adjacent sequences: A241717 A241718 A241719 * A241721 A241722 A241723

Keyword

nonn

Author

Alois P. Heinz, Apr 27 2014

Status

approved