login
A062637
Numbers k such that 71^k - 70^k is prime.
0
47, 139, 227, 2339, 4919, 21319
OFFSET
1,1
COMMENTS
Terms greater than 1000 are often only strong pseudoprimes.
a(7) > 10^5. - Robert Price, Feb 17 2014
PROG
(PARI) is(n)=ispseudoprime(71^n-70^n) \\ Charles R Greathouse IV, Jun 13 2017
KEYWORD
nonn,hard
AUTHOR
Mike Oakes, May 18 2001, May 19 2001
EXTENSIONS
a(6) from Robert Price, Feb 17 2014
STATUS
approved