A239551 Number of compositions of n such that the first part is 1 and the second differences of the parts are in {-1,0,1}.

1, 1, 1, 2, 3, 4, 6, 9, 13, 18, 24, 34, 49, 71, 100, 145, 205, 295, 423, 610, 872, 1260, 1804, 2599, 3733, 5381, 7725, 11131, 15996, 23042, 33133, 47714, 68608, 98793, 142101, 204585, 294318, 423683, 609565, 877457, 1262508, 1817205, 2614832, 3763553, 5415668

Offset: 0

Author

Alois P. Heinz, Mar 21 2014

Keywords

• nonn

Examples

			a(6) = 6: [1,1,1,1,1,1], [1,1,1,1,2], [1,1,2,2], [1,2,2,1], [1,2,3], [1,5].
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..1000

Crossrefs

Column k=1 of A239550.

Formula

a(n) ~ c * d^n, where d=1.4391340589699362028978918824612984596732704665024595117321768607966..., c=0.5987103268327131789103863373328359387911710658212178254615152936898... - Vaclav Kotesovec, May 01 2014