OFFSET
1,3
COMMENTS
Primes found and proved by PrimeForm. No more terms up to 30000.
PROG
(PARI) is(n)=ispseudoprime(2*41^n+1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
KEYWORD
hard,nonn
AUTHOR
Rick L. Shepherd, Aug 02 2008
STATUS
approved