281683

This number is a prime.

+ 281683 is the smallest prime such that if F(p) = 2*p^2-1, then F(281683), F(F(281683)), F(F(F(281683))), and F(F(F(F(281683)))) are also primes. [Opao]

Printed from the PrimePages <primes.utm.edu> © G. L. Honaker and Chris K. Caldwell