A243481 Number of isoscent sequences of length n with exactly eight descents.

17, 6867, 710088, 38504985, 1409180462, 39390143719, 903369758170, 17794252503829, 310620860769359, 4914610198933595, 71670394607559276, 975829774811610622, 12530984703191609205, 153000363388748917171, 1787972768823076763190, 20107368357857569858580

Offset

14,1

Links

Joerg Arndt and Alois P. Heinz, Table of n, a(n) for n = 14..100

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, 8]; Table[a[n], {n, 14, 40}] (* Jean-François Alcover, Feb 09 2015, after A242352 *)

Crossrefs

Column k=8 of A242352.

Sequence in context: A062659 A195813 A344148 * A287038 A198406 A198533

Adjacent sequences: A243478 A243479 A243480 * A243482 A243483 A243484

Keyword

nonn

Author

Joerg Arndt and Alois P. Heinz, Jun 05 2014

Status

approved