OFFSET
1,1
COMMENTS
Terms greater than 1000 are often only strong pseudoprimes.
No other terms less than 10^5. - Robert Price, Jul 24 2012
PROG
(PARI) is(n)=ispseudoprime(40^n-39^n) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
KEYWORD
nonn,hard
AUTHOR
Mike Oakes, May 18 2001, May 19 2001
STATUS
approved