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A321826
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a(n) = Sum_{d|n, d==1 mod 4} d^10 - Sum_{d|n, d==3 mod 4} d^10.
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3
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1, 1, -59048, 1, 9765626, -59048, -282475248, 1, 3486725353, 9765626, -25937424600, -59048, 137858491850, -282475248, -576640684048, 1, 2015993900450, 3486725353, -6131066257800, 9765626, 16679598443904, -25937424600, -41426511213648, -59048, 95367441406251, 137858491850
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OFFSET
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1,3
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LINKS
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FORMULA
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G.f.: Sum_{k>=1} (-1)^(k-1)*(2*k - 1)^10*x^(2*k-1)/(1 - x^(2*k-1)). - Ilya Gutkovskiy, Dec 22 2018
Multiplicative with a(2^e) = 1, and for an odd prime p, ((p^10)^(e+1)-1)/(p^10-1) if p == 1 (mod 4) and ((-p^10)^(e+1)-1)/(-p^10-1) if p == 3 (mod 4). - Amiram Eldar, Sep 27 2023
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MATHEMATICA
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s[n_, r_] := DivisorSum[n, #^10 &, Mod[#, 4] == r &]; a[n_] := s[n, 1] - s[n, 3]; Array[a, 30] (* Amiram Eldar, Nov 26 2018 *)
f[p_, e_] := If[Mod[p, 4] == 1, ((p^10)^(e+1)-1)/(p^10-1), ((-p^10)^(e+1)-1)/(-p^10-1)]; f[2, e_] := 1; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 60] (* Amiram Eldar, Sep 27 2023 *)
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PROG
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(PARI) apply( A321826(n)=sumdiv(n>>valuation(n, 2), d, (2-d%4)*d^10), [1..40]) \\ M. F. Hasler, Nov 26 2018
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CROSSREFS
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KEYWORD
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sign,easy,mult
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AUTHOR
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STATUS
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approved
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