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 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 (list; graph; refs; listen; history; text; internal format)
 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)^2 * theta_3(q^2) * theta_3(q^9). CROSSREFS Cf. A097057, A320124, A320125, A320126, A320127, A320128, A320130, A320132, A320133, A320134, A320135, A320136. Sequence in context: A320134 A320133 A320132 * A320130 A320128 A320127 Adjacent sequences: A320128 A320129 A320130 * A320132 A320133 A320134 KEYWORD nonn AUTHOR Seiichi Manyama, Oct 06 2018 STATUS approved

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Last modified August 9 04:00 EDT 2024. Contains 375027 sequences. (Running on oeis4.)