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Number of integer solutions to a^2 + 2*b^2 + 4*c^2 + 7*d^2 = n.
11

%I #11 Oct 08 2018 05:37:17

%S 1,2,2,4,4,4,8,10,10,10,16,12,16,28,16,20,24,24,18,28,32,8,40,32,24,

%T 34,32,32,34,56,20,40,42,40,64,56,32,32,72,28,72,64,32,60,72,84,36,88,

%U 56,66,98,40,80,40,80,104,68,44,40,92,52,116,80,42,72,100,96,84

%N Number of integer solutions to a^2 + 2*b^2 + 4*c^2 + 7*d^2 = n.

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

%H Seiichi Manyama, <a href="/A320196/b320196.txt">Table of n, a(n) for n = 0..10000</a>

%F G.f.: theta_3(q) * theta_3(q^2) * theta_3(q^4) * theta_3(q^7).

%Y Cf. A320193, A320194, A320195, A033720, A320197, A320198, A320199, A320200, A320201, A320202.

%K nonn

%O 0,2

%A _Seiichi Manyama_, Oct 07 2018