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a(n) = [q^n] Product_{d | n} theta_3(q^d), where theta_3() is the Jacobi theta function.
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%I #14 Nov 12 2019 08:11:45

%S 1,2,2,2,4,2,14,2,8,4,2,2,56,2,2,2,26,2,104,2,60,6,14,2,452,4,2,4,68,

%T 2,582,2,74,2,14,2,1460,2,14,6,688,2,782,2,108,176,2,2,5090,4,8,2,108,

%U 2,1640,2,940,6,2,2,38132,2,2,12,364,2,1142,2,100,2,1266,2,62528

%N a(n) = [q^n] Product_{d | n} theta_3(q^d), where theta_3() is the Jacobi theta function.

%C Also the number of integer solutions (a_1, a_2, ... , a_{d(n)}) to the equation Sum_{d | n} d * a_d^2 = n, where d(n) is the number of divisors of n.

%H Seiichi Manyama, <a href="/A320305/b320305.txt">Table of n, a(n) for n = 0..1000</a>

%Y Cf. A000005, A000122.

%K nonn

%O 0,2

%A _Seiichi Manyama_, Oct 10 2018