OFFSET
0,2
COMMENTS
a(n) is the Euler transform of A010860. - Alois P. Heinz, Oct 17 2008
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..1000
N. J. A. Sloane, Transforms
FORMULA
a(0) = 1, a(n) = (21/n)*Sum_{k=1..n} A000203(k)*a(n-k) for n > 0. - Seiichi Manyama, Mar 27 2017
MAPLE
with (numtheory): a:= proc(n) option remember; `if`(n=0, 1, add (add (d*21, d=divisors(j)) *a(n-j), j=1..n)/n) end: seq (a(n), n=0..40); # Alois P. Heinz, Oct 17 2008
MATHEMATICA
CoefficientList[Series[1/QPochhammer[x]^21, {x, 0, 30}], x] (* Indranil Ghosh, Mar 27 2017 *)
PROG
(PARI) Vec(1/eta(x)^21 + O(x^30)) \\ Indranil Ghosh, Mar 27 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
David W. Wilson, Jun 14 1998
STATUS
approved