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A341222
Expansion of (-1 + Product_{k>=1} 1 / (1 - x^k))^4.
11
1, 8, 36, 124, 362, 944, 2266, 5100, 10903, 22340, 44168, 84692, 158137, 288452, 515344, 903740, 1558465, 2646820, 4432964, 7329916, 11977507, 19358524, 30970444, 49077936, 77081679, 120054268, 185514428, 284540060, 433360308, 655622392, 985604644, 1472751228
OFFSET
4,2
LINKS
FORMULA
a(n) ~ A023003(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, 4):
seq(a(n), n=4..35); # Alois P. Heinz, Feb 07 2021
MATHEMATICA
nmax = 35; CoefficientList[Series[(-1 + Product[1/(1 - x^k), {k, 1, nmax}])^4, {x, 0, nmax}], x] // Drop[#, 4] &
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Feb 07 2021
STATUS
approved