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A321828
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a(n) = Sum_{d|n, d==1 mod 4} d^12 - Sum_{d|n, d==3 mod 4} d^12.
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4
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1, 1, -531440, 1, 244140626, -531440, -13841287200, 1, 282429005041, 244140626, -3138428376720, -531440, 23298085122482, -13841287200, -129746094281440, 1, 582622237229762, 282429005041, -2213314919066160, 244140626, 7355813669568000
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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)^12*x^(2*k-1)/(1 - x^(2*k-1)). - Ilya Gutkovskiy, Dec 22 2018
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MATHEMATICA
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s[n_, r_] := DivisorSum[n, #^12 &, Mod[#, 4] == r &]; a[n_] := s[n, 1] - s[n, 3]; Array[a, 30] (* Amiram Eldar, Nov 26 2018 *)
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PROG
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(PARI) apply( A321828(n)=sumdiv(n>>valuation(n, 2), d, (2-d%4)*d^12), [1..40]) \\ M. F. Hasler, Nov 26 2018
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CROSSREFS
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KEYWORD
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sign,mult
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AUTHOR
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STATUS
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approved
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