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 A007517 a(n) = phi(n) * (sigma(n) - n). 1
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS G. C. Greubel, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A000010(n)*A001065(n). - Michel Marcus, Mar 22 2018 MAPLE with(numtheory): seq(phi(n)*(sigma(n)-n), n=1..60); # Muniru A Asiru, Mar 22 2018 MATHEMATICA Table[EulerPhi[n](DivisorSigma[1, n]-n), {n, 60}] (* Harvey P. Dale, Mar 16 2013 *) PROG (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 CROSSREFS Cf. A000010, A000203, A001065. Sequence in context: A222423 A059909 A145177 * A072946 A134000 A127730 Adjacent sequences:  A007514 A007515 A007516 * A007518 A007519 A007520 KEYWORD nonn AUTHOR STATUS approved

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Last modified October 15 00:14 EDT 2019. Contains 328025 sequences. (Running on oeis4.)