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A103638
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a(n) = Sum_{d|n, d==2 mod 3} d^2.
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3
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0, 4, 0, 4, 25, 4, 0, 68, 0, 29, 121, 4, 0, 200, 25, 68, 289, 4, 0, 429, 0, 125, 529, 68, 25, 680, 0, 200, 841, 29, 0, 1092, 121, 293, 1250, 4, 0, 1448, 0, 493, 1681, 200, 0, 2061, 25, 533, 2209, 68, 0, 2529, 289, 680, 2809, 4, 146, 3400, 0, 845, 3481, 429, 0, 3848
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OFFSET
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1,2
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LINKS
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MATHEMATICA
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a[n_] := DivisorSum[n, #^2 &, Mod[#, 3] == 2 &]; Array[a, 100] (* Amiram Eldar, Jun 30 2023 *)
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PROG
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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