A243479 Number of isoscent sequences of length n with exactly six descents.

2, 570, 34643, 1139465, 26298831, 479669603, 7386945631, 100099764774, 1227140160022, 13879804132399, 146957303797639, 1472647088474040, 14087369324642004, 129522280702233381, 1150891407181302417, 9927963973481921295, 83454334937159452579

Offset: 11

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 = 11..100

Crossrefs

Column k=6 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, 6]; Table[a[n], {n, 11, 40}] (* Jean-François Alcover, Feb 09 2015, after A242352 *)