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A050448
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a(n) = Sum_{d|n, d==1 (mod 4)} d^4.
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2
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1, 1, 1, 1, 626, 1, 1, 1, 6562, 626, 1, 1, 28562, 1, 626, 1, 83522, 6562, 1, 626, 194482, 1, 1, 1, 391251, 28562, 6562, 1, 707282, 626, 1, 1, 1185922, 83522, 626, 6562, 1874162, 1, 28562, 626, 2825762, 194482, 1, 1, 4107812, 1, 1, 1
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OFFSET
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1,5
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LINKS
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MATHEMATICA
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a[n_] := DivisorSum[n, #^4 &, Mod[#, 4] == 1 &]; Array[a, 50] (* Amiram Eldar, Jul 08 2023 *)
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PROG
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(PARI) a(n) = sumdiv(n, d, if ((d%4)==1, d^4)); \\ Michel Marcus, Aug 16 2021
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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