A281460 Expansion of Product_{k>=1} (1 + x^(7*k-2))*(1 + x^(7*k-5)).

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

Vaclav Kotesovec, Table of n, a(n) for n = 0..10000

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

Cf. A035433, A281455, A281458.

Sequence in context: A063883 A079691 A104450 * A035226 A126043 A360170

Adjacent sequences: A281457 A281458 A281459 * A281461 A281462 A281463

Keyword

nonn

Author

Vaclav Kotesovec, Jan 22 2017

Status

approved