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.

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

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: A347733 A347798 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