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A341221
Expansion of (-1 + Product_{k>=1} 1 / (1 - x^k))^3.
11
1, 6, 21, 59, 144, 321, 669, 1323, 2511, 4604, 8202, 14253, 24241, 40449, 66363, 107234, 170910, 269004, 418566, 644436, 982536, 1484482, 2223942, 3305484, 4876620, 7144455, 10398123, 15039564, 21624678, 30919323, 43973708, 62222844, 87619212, 122810585
OFFSET
3,2
LINKS
FORMULA
a(n) ~ A000716(n). - Vaclav Kotesovec, Feb 20 2021
MAPLE
b:= proc(n, k) option remember; `if`(k<2, `if`(n=0, 1-k, combinat[
numbpart](n)), (q-> add(b(j, q)*b(n-j, k-q), j=0..n))(iquo(k, 2)))
end:
a:= n-> b(n, 3):
seq(a(n), n=3..36); # Alois P. Heinz, Feb 07 2021
MATHEMATICA
nmax = 36; CoefficientList[Series[(-1 + Product[1/(1 - x^k), {k, 1, nmax}])^3, {x, 0, nmax}], x] // Drop[#, 3] &
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Feb 07 2021
STATUS
approved