login
A320131
Number of integer solutions to a^2 + b^2 + 2*c^2 + 9*d^2 = n.
9
1, 4, 6, 8, 12, 8, 8, 16, 6, 14, 32, 20, 40, 48, 16, 32, 44, 28, 54, 72, 40, 64, 72, 16, 40, 52, 56, 92, 96, 56, 32, 80, 38, 48, 104, 64, 102, 144, 52, 32, 112, 44, 128, 168, 68, 136, 128, 96, 104, 132, 62, 144, 176, 104, 172, 96, 112, 112, 192, 116, 96, 240, 96, 176
OFFSET
0,2
COMMENTS
a(n) > 0 for n >= 0.
LINKS
FORMULA
G.f.: theta_3(q)^2 * theta_3(q^2) * theta_3(q^9).
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Oct 06 2018
STATUS
approved