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

11,1

Links

Joerg Arndt and Alois P. Heinz, Table of n, a(n) for n = 11..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, 6]; Table[a[n], {n, 11, 40}] (* Jean-François Alcover, Feb 09 2015, after A242352 *)

Crossrefs

Column k=6 of A242352.

Sequence in context: A285690 A201603 A200964 * A049364 A159529 A195001

Adjacent sequences: A243476 A243477 A243478 * A243480 A243481 A243482

Keyword

nonn

Author

Joerg Arndt and Alois P. Heinz, Jun 05 2014

Status

approved