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 A284900 a(n) = Sum_{d|n} (-1)^(n/d+1)*d^4. 10
 1, 15, 82, 239, 626, 1230, 2402, 3823, 6643, 9390, 14642, 19598, 28562, 36030, 51332, 61167, 83522, 99645, 130322, 149614, 196964, 219630, 279842, 313486, 391251, 428430, 538084, 574078, 707282, 769980, 923522, 978671, 1200644, 1252830, 1503652, 1587677 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Multiplicative because this sequence is the Dirichlet convolution of A000583 and A062157 which are both multiplicative. - Andrew Howroyd, Jul 20 2018 LINKS Seiichi Manyama, Table of n, a(n) for n = 1..10000 J. W. L. Glaisher, On the representations of a number as the sum of two, four, six, eight, ten, and twelve squares, Quart. J. Math. 38 (1907), 1-62 (see p. 4 and p. 8). FORMULA G.f.: Sum_{k>=1} k^4*x^k/(1 + x^k). - Ilya Gutkovskiy, Apr 07 2017 MATHEMATICA Table[Sum[(-1)^(n/d + 1)*d^4, {d, Divisors[n]}], {n, 50}] (* Indranil Ghosh, Apr 05 2017 *) PROG (PARI) a(n) = sumdiv(n, d, (-1)^(n/d + 1)*d^4); \\ Indranil Ghosh, Apr 05 2017 (Python) from sympy import divisors print [sum([(-1)**(n/d + 1)*d**4 for d in divisors(n)]) for n in xrange(1, 51)] # Indranil Ghosh, Apr 05 2017 CROSSREFS Sum_{d|n} (-1)^(n/d+1)*d^k: A000593 (k=1), A078306 (k=2), A078307 (k=3), this sequence (k=4), A284926 (k=5), A284927 (k=6). Cf. A000583, A062157. Sequence in context: A213552 A060581 A253222 * A065103 A279395 A270768 Adjacent sequences:  A284897 A284898 A284899 * A284901 A284902 A284903 KEYWORD nonn,mult AUTHOR Seiichi Manyama, Apr 05 2017 STATUS approved

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Last modified December 6 07:09 EST 2019. Contains 329785 sequences. (Running on oeis4.)