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A281460
Expansion of Product_{k>=1} (1 + x^(7*k-2))*(1 + x^(7*k-5)).
1
1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 2, 0, 2, 1, 1, 2, 0, 3, 0, 3, 1, 2, 3, 1, 5, 0, 5, 2, 3, 5, 1, 7, 1, 7, 3, 5, 7, 2, 11, 1, 11, 5, 7, 11, 3, 15, 3, 15, 7, 11, 15, 5, 22, 4, 22, 11, 15, 22, 8, 30, 7, 30, 15, 22, 30, 12, 42, 10, 42, 22, 30, 42, 17, 56
OFFSET
0,15
COMMENTS
Convolution of A281455 and A281458.
LINKS
FORMULA
a(n) ~ exp(sqrt(2*n/21)*Pi) / (2^(5/4)*21^(1/4)*n^(3/4)) * (1 - (3*sqrt(21/2)/(8*Pi) + 11*Pi/(84*sqrt(42))) / sqrt(n)). - Vaclav Kotesovec, Jan 22 2017, extended Jan 24 2017
MATHEMATICA
nmax = 100; CoefficientList[Series[Product[(1 + x^(7*k-2))*(1 + x^(7*k-5)), {k, 1, nmax}], {x, 0, nmax}], x]
CROSSREFS
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, Jan 22 2017
STATUS
approved