A236932 Number of integer solutions to a^2 + b^2 + c^2 + 7*d^2 = n.

1, 6, 12, 8, 6, 24, 24, 2, 24, 54, 40, 36, 56, 72, 48, 24, 66, 96, 84, 40, 72, 144, 24, 12, 120, 102, 120, 80, 98, 132, 72, 64, 84, 240, 160, 48, 198, 180, 120, 72, 136, 240, 240, 84, 84, 312, 120, 96, 248, 246, 180, 96, 216, 228, 240, 80, 156, 360, 216, 120, 168

Offset: 0

Author

N. J. A. Sloane, Feb 16 2014

Keywords

• nonn

Links

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

Crossrefs

For number of solutions to a^2 + b^2 + c^2 + k*d^2 = n for k = 1, 2, 3, 4, 5, 6, 7, 8, 12 see A000118, A236928, A236926, A236923, A236930, A236931, A236932, A236927, A236933.

Programs

Maple

See A236924.

Formula

G.f.: theta_3(q)^3*theta_3(q^7), where theta_3() is the Jacobi theta function. - Ilya Gutkovskiy, Aug 01 2018