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A007517
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a(n) = phi(n) * (sigma(n) - n).
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1
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0, 1, 2, 6, 4, 12, 6, 28, 24, 32, 10, 64, 12, 60, 72, 120, 16, 126, 18, 176, 132, 140, 22, 288, 120, 192, 234, 336, 28, 336, 30, 496, 300, 320, 312, 660, 36, 396, 408, 800, 40, 648, 42, 800, 792, 572, 46, 1216, 336, 860, 672, 1104, 52, 1188, 680
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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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MAPLE
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with(numtheory): seq(phi(n)*(sigma(n)-n), n=1..60); # Muniru A Asiru, Mar 22 2018
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MATHEMATICA
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Table[EulerPhi[n](DivisorSigma[1, n]-n), {n, 60}] (* Harvey P. Dale, Mar 16 2013 *)
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PROG
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(GAP) List([1..60], n->Phi(n)*(Sigma(n)-n)); # Muniru A Asiru, Mar 22 2018
(PARI) for(n=1, 50, print1(eulerphi(n)*(sigma(n) - n), ", ")) \\ G. C. Greubel, Mar 22 2018
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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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