OFFSET
1,1
COMMENTS
No further terms up to 41161739. - Harvey P. Dale, Dec 23 2011
No further terms up to 250000000. - Sean A. Irvine, Aug 01 2023
From Jason Yuen, Apr 21 2024: (Start)
Primes p such that prime(p)^2 == 1 (mod p).
No further terms up to 4*10^19. (End)
EXAMPLE
5 belongs in the sequence because gcd(5, P_5^2 -1) = gcd(5, 120) = 5.
MATHEMATICA
Do[ If[ GCD[ Prime[n], Prime[ Prime[n]]^2 - 1] != 1, Print[ Prime[n]] ], {n, 1, 10^6} ]
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Robert G. Wilson v, Oct 26 2001
STATUS
approved