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A007517 a(n) = phi(n) * (sigma(n) - n). 0
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

Table of n, a(n) for n=1..55.

MATHEMATICA

Table[EulerPhi[n](DivisorSigma[1, n]-n), {n, 60}] (* Harvey P. Dale, Mar 16 2013 *)

CROSSREFS

Cf. A000010, A000203.

Sequence in context: A222423 A059909 A145177 * A072946 A134000 A127730

Adjacent sequences:  A007514 A007515 A007516 * A007518 A007519 A007520

KEYWORD

nonn

AUTHOR

Walter Nissen

STATUS

approved

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Last modified March 25 11:54 EDT 2017. Contains 284076 sequences.