OFFSET
1,1
COMMENTS
2-pseudoprimes of the form n*p^2*q^2, where p and q are distinct Wieferich primes (A001220).
Unless there are other Wieferich primes besides 1093 and 3511, the sequence is the intersection of A247830 and A247831. - Max Alekseyev, Nov 26 2017
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
PROG
(PARI) forstep(n=236641458619975501, 4.489e31, 723664277589495060, if(Mod(2, n)^(n-1)==1, print1(n", ")))
CROSSREFS
KEYWORD
nonn
AUTHOR
Charles R Greathouse IV, Nov 18 2012
STATUS
approved