A306030 Number of length-n restricted growth strings (RGS) with growth <= six and first element in [6].

1, 6, 57, 685, 9780, 160201, 2943277, 59687920, 1320233315, 31557691541, 809161436022, 22121068343155, 641530646758325, 19651776950222806, 633510644286624717, 21422880077590022265, 757789084383273607060, 27969244566731240796621, 1074750913823536151018737

Offset: 0

Author

Alois P. Heinz, Jun 17 2018

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..431

Crossrefs

Column k=6 of A306024.

Cf. A305966.

Programs

Maple

b:= proc(n, m) option remember; `if`(n=0, 1,
      add(b(n-1, max(m, j)), j=1..m+6))
    end:
a:= n-> b(n, 0):
seq(a(n), n=0..25);
# second Maple program:
a:= n-> n!*coeff(series(exp(add((exp(j*x)-1)/j, j=1..6)), x, n+1), x, n):
seq(a(n), n=0..25);

Formula

E.g.f.: exp(Sum_{j=1..6} (exp(j*x)-1)/j).