A281461 - OEIS

%I #6 Jan 24 2017 10:06:36

%S 1,0,0,1,1,0,0,1,0,0,1,1,0,1,2,1,0,2,2,0,1,3,1,0,3,3,0,2,5,2,1,5,5,1,

%T 3,7,3,1,7,7,1,5,11,5,2,11,11,2,7,15,7,3,15,15,4,11,22,11,6,22,22,6,

%U 15,30,15,8,30,30,9,22,42,22,13,42,42,14,30,56

%N Expansion of Product_{k>=1} (1 + x^(7*k-3))*(1 + x^(7*k-4)).

%C Convolution of A281456 and A281457.

%H Vaclav Kotesovec, <a href="/A281461/b281461.txt">Table of n, a(n) for n = 0..10000</a>

%F a(n) ~ exp(sqrt(2*n/21)*Pi) / (2^(5/4)*21^(1/4)*n^(3/4)) * (1 - (3*sqrt(21/2)/(8*Pi) + 23*Pi/(84*sqrt(42))) / sqrt(n)). - _Vaclav Kotesovec_, Jan 22 2017, extended Jan 24 2017

%t nmax = 100; CoefficientList[Series[Product[(1 + x^(7*k-3))*(1 + x^(7*k-4)), {k, 1, nmax}], {x, 0, nmax}], x]

%Y Cf. A035435, A281456, A281457.

%K nonn

%O 0,15

%A _Vaclav Kotesovec_, Jan 22 2017