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A320240
Expansion of theta_3(q) * theta_3(q^3) * theta_3(q^5) * theta_3(q^7), where theta_3() is the Jacobi theta function.
2
1, 2, 0, 2, 6, 2, 4, 6, 8, 14, 4, 12, 18, 12, 12, 8, 34, 12, 8, 32, 10, 28, 0, 16, 44, 18, 16, 14, 54, 8, 12, 48, 32, 52, 28, 32, 42, 40, 8, 44, 92, 28, 16, 56, 28, 30, 44, 12, 86, 74, 8, 32, 72, 24, 40, 104, 72, 56, 32, 56, 56, 112, 8, 38, 166, 24, 36, 40, 56, 88, 52
OFFSET
0,2
COMMENTS
Also the number of integer solutions (a_1, a_2, a_3, a_4) to the equation a_1^2 + 3*a_2^2 + 5*a_3^2 + 7*a_4^2 = n.
LINKS
Eric Weisstein's World of Mathematics, Jacobi Theta Functions
CROSSREFS
Product_{k=1..m} theta_3(q^(2*k-1)): A000122 (m=1), A033716 (m=2), A320239 (m=3), this sequence (m=4).
Cf. A320078.
Sequence in context: A320239 A033727 A033757 * A320992 A320078 A136426
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Oct 08 2018
STATUS
approved