OFFSET
0,3
COMMENTS
Convolution inverse of A001970.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..3000
FORMULA
G.f.: Product_{k>=1} (1 - x^k)^A000041(k).
MAPLE
with(numtheory): with(combinat):
b:= proc(n) option remember; `if`(n=0, 1, add(add(d*
numbpart(d), d=divisors(j))*b(n-j), j=1..n)/n)
end:
a:= proc(n) option remember; `if`(n=0, 1,
-add(b(n-i)*a(i), i=0..n-1))
end:
seq(a(n), n=0..60); # Alois P. Heinz, Mar 07 2018
MATHEMATICA
nmax = 45; CoefficientList[Series[Product[(1 - x^k)^PartitionsP[k], {k, 1, nmax}], {x, 0, nmax}], x]
CROSSREFS
KEYWORD
sign
AUTHOR
Ilya Gutkovskiy, Mar 07 2018
STATUS
approved