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A261634
Expansion of Product_{k>=0} (1+x^(4*k+1))^3.
3
1, 3, 3, 1, 0, 3, 9, 9, 3, 3, 12, 18, 12, 6, 18, 37, 33, 15, 22, 54, 66, 42, 36, 81, 114, 84, 57, 112, 189, 171, 109, 156, 279, 294, 201, 222, 405, 486, 360, 328, 564, 747, 617, 504, 783, 1123, 1017, 783, 1065, 1602, 1605
OFFSET
0,2
FORMULA
a(n) ~ exp(Pi*sqrt(n)/2) / (2^(5/4) * n^(3/4)).
MATHEMATICA
nmax=50; CoefficientList[Series[Product[(1+x^(4*k+1))^3, {k, 0, nmax}], {x, 0, nmax}], x]
CROSSREFS
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, Aug 27 2015
STATUS
approved