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Number of integer solutions to a^2 + b^2 + 2*c^2 + 4*d^2 = n.
14

%I #11 Oct 06 2018 12:06:32

%S 1,4,6,8,14,16,20,32,30,28,40,40,36,48,48,32,62,72,42,72,72,64,100,96,

%T 68,84,120,80,112,112,48,128,126,80,108,128,98,144,180,96,136,168,160,

%U 168,180,112,144,192,132,228,126,144,216,208,200,160,240,144,280,232

%N Number of integer solutions to a^2 + b^2 + 2*c^2 + 4*d^2 = n.

%C a(n) > 0 for n >= 0.

%H Seiichi Manyama, <a href="/A320125/b320125.txt">Table of n, a(n) for n = 0..10000</a>

%F G.f.: theta_3(q)^2 * theta_3(q^2) * theta_3(q^4).

%Y Cf. A097057, A320124, A320126, A320127, A320128.

%K nonn

%O 0,2

%A _Seiichi Manyama_, Oct 06 2018