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A092341
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a(0)=1, a(n) = sigma_3(3n).
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2
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1, 28, 252, 757, 2044, 3528, 6813, 9632, 16380, 20440, 31752, 37296, 55261, 61544, 86688, 95382, 131068, 137592, 183960, 192080, 257544, 260408, 335664, 340704, 442845, 441028, 553896, 551881, 703136, 682920, 858438, 834176, 1048572, 1008324, 1238328, 1213632
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OFFSET
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0,2
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LINKS
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FORMULA
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Sum_{k=1..n} a(k) ~ (83*zeta(4)/12) * n^4. - Amiram Eldar, Dec 12 2023
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MATHEMATICA
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Join[{1}, DivisorSigma[3, 3*Range[40]]] (* Harvey P. Dale, Feb 02 2012 *)
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PROG
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(PARI) a(n) = if(n < 1, 1, sigma(3*n, 3)); \\ Amiram Eldar, Dec 12 2023
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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