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A200905 3*phi(n), where phi (A000010) is the Euler totient function. 2
3, 3, 6, 6, 12, 6, 18, 12, 18, 12, 30, 12, 36, 18, 24, 24, 48, 18, 54, 24, 36, 30, 66, 24, 60, 36, 54, 36, 84, 24, 90, 48, 60, 48, 72, 36, 108, 54, 72, 48, 120, 36, 126, 60, 72, 66, 138, 48, 126, 60, 96, 72, 156, 54, 120, 72, 108, 84, 174, 48, 180, 90, 108, 96, 144, 60, 198, 96, 132, 72, 210, 72, 216, 108 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

M. Picquet, Applications de la representation des courbes du troisieme degre, Journal de l'École Polytechnique, Paris, 35 (1884), 31-100. See p. 98.

MATHEMATICA

Table[3 EulerPhi[n], {n, 100}] (* Vincenzo Librandi, Mar 05 2013 *)

PROG

(PARI) a(n)=3*eulerphi(n) \\ Charles R Greathouse IV, Mar 05 2013

(MAGMA) [3*EulerPhi(n): n in [1..100]]; // Vincenzo Librandi, Mar 05 2013

CROSSREFS

Sequence in context: A219627 A131942 A240204 * A280510 A292128 A117775

Adjacent sequences:  A200902 A200903 A200904 * A200906 A200907 A200908

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Nov 23 2011

STATUS

approved

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Last modified October 21 04:26 EDT 2019. Contains 328291 sequences. (Running on oeis4.)