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A066936 Integers k such that prime(k)-1 == 0 (mod phi(k)) where prime(n)=A000040(n) is the n-th prime and phi(n)=A000010(n) is the Euler totient function. 3
1, 2, 3, 4, 6, 10, 11, 12, 14, 18, 21, 24, 30, 38, 42, 46, 67, 84, 87, 110, 121, 136, 159, 279, 306, 378, 428, 439, 516, 662, 682, 726, 1046, 1110, 1199, 1410, 1687, 2160, 2244, 2438, 2450, 2612, 2614, 2654, 3270, 3477, 3829, 7107, 7178, 8682, 9260 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..94

MATHEMATICA

Select[Range[1, 10000], Mod[Prime[ # ]-1, EulerPhi[ # ]]==0&]

PROG

(PARI) { default(primelimit, 4294965247); n=0; for (m=1, 10^10, if ((prime(m) - 1) % eulerphi(m) == 0, write("b066936.txt", n++, " ", m); if (n==1000, return)) ) } \\ Harry J. Smith, Apr 09 2010

(MAGMA) [n:n in [1..10000]| IsIntegral((NthPrime(n)-1)/EulerPhi(n))]; // Marius A. Burtea, Mar 25 2019

CROSSREFS

Cf. A000010, A000040.

Sequence in context: A122397 A339670 A047417 * A067027 A275108 A005457

Adjacent sequences:  A066933 A066934 A066935 * A066937 A066938 A066939

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Jan 24 2002

EXTENSIONS

Edited by Dean Hickerson, Jan 27 2002

Definition corrected by Harry J. Smith, Apr 09 2010

STATUS

approved

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Last modified April 17 05:36 EDT 2021. Contains 343059 sequences. (Running on oeis4.)