A320196 Number of integer solutions to a^2 + 2*b^2 + 4*c^2 + 7*d^2 = n.

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, 34, 32, 32, 34, 56, 20, 40, 42, 40, 64, 56, 32, 32, 72, 28, 72, 64, 32, 60, 72, 84, 36, 88, 56, 66, 98, 40, 80, 40, 80, 104, 68, 44, 40, 92, 52, 116, 80, 42, 72, 100, 96, 84

Offset

0,2

Comments

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

Links

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

Formula

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

Crossrefs

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

Sequence in context: A033728 A033744 A133389 * A033740 A303800 A305245

Adjacent sequences: A320193 A320194 A320195 * A320197 A320198 A320199

Keyword

nonn

Author

Seiichi Manyama, Oct 07 2018

Status

approved