A320128 Number of integer solutions to a^2 + b^2 + 2*c^2 + 7*d^2 = n.

1, 4, 6, 8, 12, 8, 8, 18, 14, 24, 40, 32, 40, 40, 32, 28, 36, 64, 46, 72, 72, 16, 56, 40, 40, 88, 72, 80, 82, 64, 44, 64, 86, 96, 128, 144, 64, 64, 136, 44, 136, 160, 80, 144, 128, 120, 92, 128, 104, 164, 158, 96, 168, 80, 144, 160, 168, 108, 104, 232, 108, 168, 192, 82

Offset: 0

Author

Seiichi Manyama, Oct 06 2018

Keywords

• nonn

Comments

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

Links

• Seiichi Manyama, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A097057, A320124, A320125, A320126, A320127.

Formula

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