A067933 Primes p such that p == -1 (mod phi(p-1)).

2, 3, 5, 7, 11, 31, 71, 2591, 131071

Offset: 1

Author

Benoit Cloitre, Feb 22 2002

Keywords

• nonn
• more

Comments

No more terms up to 373587883 (the 20 millionth prime).

Crossrefs

Cf. A000010, A008330.

Programs

Mathematica

Do[p = Prime[n]; If[ Mod[p + 1, EulerPhi[p - 1]] == 0, Print[p]], {n, 1, 10^8}] (* Cloitre *)
Select[Prime[Range[10^5]], Mod[#, EulerPhi[# - 1]] == EulerPhi[# - 1] - 1 &] (* Alonso del Arte, Sep 26 2011 *)

PARI

list(lim) = forprime(p  = 1, lim, if(!((p+1) % eulerphi(p-1)), print1(p,", "))); \\ Amiram Eldar, Apr 18 2025

Extensions

Edited by Robert G. Wilson v, Feb 27 2002