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

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 = 14..100

Crossrefs

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