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A099979
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Bisection of A001157: sigma_2(2n).
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3
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5, 21, 50, 85, 130, 210, 250, 341, 455, 546, 610, 850, 850, 1050, 1300, 1365, 1450, 1911, 1810, 2210, 2500, 2562, 2650, 3410, 3255, 3570, 4100, 4250, 4210, 5460, 4810, 5461, 6100, 6090, 6500, 7735, 6850, 7602, 8500, 8866, 8410, 10500, 9250, 10370
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OFFSET
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1,1
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LINKS
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FORMULA
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a(n) = A001157(2*n) = sigma_2(2*n).
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EXAMPLE
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a(1) = sigma_2(2*1) = 1 + 2^2 = 5.
a(2) = sigma_2(2*2) = 1 + 2^2 + 4^2 = 21.
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MAPLE
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with(numtheory): seq(sigma[2](2*n), n=1..50); # C. Ronaldo
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MATHEMATICA
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Table[DivisorSigma[2, 2n], {n, 1, 47}] (* Indranil Ghosh, Mar 03 2017 *)
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PROG
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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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EXTENSIONS
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More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Jan 18 2005
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STATUS
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approved
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