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A306030
Number of length-n restricted growth strings (RGS) with growth <= six and first element in [6].
3
1, 6, 57, 685, 9780, 160201, 2943277, 59687920, 1320233315, 31557691541, 809161436022, 22121068343155, 641530646758325, 19651776950222806, 633510644286624717, 21422880077590022265, 757789084383273607060, 27969244566731240796621, 1074750913823536151018737
OFFSET
0,2
LINKS
FORMULA
E.g.f.: exp(Sum_{j=1..6} (exp(j*x)-1)/j).
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);
CROSSREFS
Column k=6 of A306024.
Cf. A305966.
Sequence in context: A060435 A153851 A141372 * A152170 A087659 A369071
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Jun 17 2018
STATUS
approved