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 A236930 Number of integer solutions to a^2 + b^2 + c^2 + 5*d^2 = n. 10
 1, 6, 12, 8, 6, 26, 36, 24, 28, 42, 72, 72, 8, 48, 108, 48, 54, 64, 84, 120, 26, 72, 144, 88, 84, 126, 216, 80, 24, 180, 156, 192, 92, 96, 288, 144, 42, 144, 240, 144, 168, 252, 144, 168, 72, 182, 396, 184, 72, 258, 372, 192, 48, 208, 360, 312, 252, 160, 360, 360, 48 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Seiichi Manyama, Table of n, a(n) for n = 0..10000 FORMULA G.f.: theta_3(q)^3*theta_3(q^5), where theta_3() is the Jacobi theta function. - Ilya Gutkovskiy, Aug 01 2018 MAPLE See A236924. MATHEMATICA 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. Join[{1}, Table[Length[Reduce[a^2+b^2+c^2+5d^2==n, {a, b, c, d}, Integers]], {n, 60}]] (* Harvey P. Dale, Jul 02 2017 *) CROSSREFS Sequence in context: A281484 A236931 A028659 * A028643 A236923 A028627 Adjacent sequences:  A236927 A236928 A236929 * A236931 A236932 A236933 KEYWORD nonn AUTHOR N. J. A. Sloane, Feb 16 2014 STATUS approved

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Last modified October 22 14:48 EDT 2018. Contains 316488 sequences. (Running on oeis4.)