A243484 Number of isoscent sequences of length n with maximal number of descents.

1, 1, 2, 1, 6, 2, 28, 10, 1, 98, 22, 2, 570, 130, 17, 1, 1842, 337, 38, 2, 13104, 2437, 318, 26, 1, 45188, 7126, 805, 58, 2, 387323, 61504, 7496, 658, 37, 1, 1422382, 196200, 20978, 1631, 82, 2, 14272601, 1971561, 220497, 19175, 1216, 50, 1, 54989728, 6713935

Offset: 0

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 = 0..100

Programs

Mathematica

b[n_, i_, t_] := b[n, i, t] = If[n<1, 1, Expand[ Sum[If[jJean-François Alcover, Feb 09 2015, after A242352 *)

Formula

a(n) = A242352(n,n+2-ceiling(2*sqrt(n+1))).