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Number of integer solutions to a^2 + 2*b^2 + 2*c^2 + 7*d^2 = n.
7

%I #11 Oct 08 2018 03:49:19

%S 1,2,4,8,6,8,8,2,16,18,24,36,24,24,16,24,26,32,60,40,40,48,8,12,56,34,

%T 72,80,34,44,24,64,44,80,96,48,102,60,40,72,72,80,144,84,52,104,40,96,

%U 120,82,92,96,120,76,80,80,84,120,136,120,72,120,64,194,102

%N Number of integer solutions to a^2 + 2*b^2 + 2*c^2 + 7*d^2 = n.

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

%H Seiichi Manyama, <a href="/A320153/b320153.txt">Table of n, a(n) for n = 0..10000</a>

%F G.f.: theta_3(q) * theta_3(q^2)^2 * theta_3(q^7).

%Y Cf. A320149, A320150, A236924, A320151, A320152.

%K nonn

%O 0,2

%A _Seiichi Manyama_, Oct 06 2018