OFFSET
21,3
LINKS
Joerg Arndt and Alois P. Heinz, Table of n, a(n) for n = 21..1000
FORMULA
a(n) ~ c * 2^n, where c = 0.00000076865174785709491795394332754061911033555649913960925841174268897641... . - Vaclav Kotesovec, Sep 07 2014
MAPLE
b:= proc(n, i) option remember; `if`(n=0, 1, series(
add(b(n-j, i+1)*`if`(i=j, x, 1), j=1..n), x, 7))
end:
a:= n-> coeff(b(n, 1), x, 6):
seq(a(n), n=21..60);
MATHEMATICA
b[n_, i_] := b[n, i] = If[n == 0, 1, Series[Sum[b[n-j, i+1]*If[i == j, x, 1], {j, 1, n}], {x, 0, 7}]]; a[n_] := SeriesCoefficient[b[n, 1], {x, 0, 6}]; Table[a[n], {n, 21, 60}] (* Jean-François Alcover, Nov 07 2014, after Maple *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Joerg Arndt and Alois P. Heinz, Apr 11 2014
STATUS
approved