A264910 Number of 5-ascent sequences of length n with no consecutive repeated letters.

1, 1, 5, 30, 195, 1380, 10555, 86815, 764350, 7174420, 71532369, 755136887, 8415519048, 98744576456, 1216948265335, 15718032335081, 212330461568282, 2994374695258034, 44008250794756373, 672986694107199687, 10692604102273015636, 176266660430175342285

Offset: 0

Author

Alois P. Heinz, Nov 28 2015

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..200
• S. Kitaev, J. Remmel, p-Ascent Sequences, arXiv:1503.00914 [math.CO], 2015

Crossrefs

Column k=5 of A264909.

Programs

Maple

b:= proc(n, i, t) option remember; `if`(n<1, 1, add(
      `if`(j=i, 0, b(n-1, j, t+`if`(j>i, 1, 0))), j=0..t+5))
    end:
a:= n-> (b(n-1, 0$2)):
seq(a(n), n=0..30);

Mathematica

b[n_, i_, t_] := b[n, i, t] = If[n<1, 1, Sum[If[j==i, 0, b[n-1, j, t + If[j>i, 1, 0]]], {j, 0, t+5}]];
a[n_] := b[n-1, 0, 0];
Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Aug 14 2017, translated from Maple *)