A243480 Number of isoscent sequences of length n with exactly seven descents.

130, 18196, 1027497, 35855578, 920132845, 19024724767, 334824869566, 5199938158961, 73073359931844, 946309985456857, 11449696018832655, 130815643776548834, 1423250326223813866, 14845562100052915605, 149281547622659687547, 1453772869428542126084

Offset: 13

Author

Joerg Arndt and Alois P. Heinz, Jun 05 2014

Keywords

• nonn

Links

• Joerg Arndt and Alois P. Heinz, Table of n, a(n) for n = 13..100

Crossrefs

Column k=7 of A242352.

Programs

Mathematica

b[n_, i_, t_] := b[n, i, t] = If[n < 1, 1, Expand[Sum[ If[j < i, x, 1] *b[n - 1, j, t + If[j == i, 1, 0]], {j, 0, t + 1}]]]; a[n_] := Coefficient[b[n - 1, 0, 0], x, 7]; Table[a[n], {n, 13, 40}] (* Jean-François Alcover, Feb 09 2015, after A242352 *)