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A062606
Numbers k such that 40^k - 39^k is prime.
0
2, 37, 61, 227, 1163, 2473
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
KEYWORD
nonn,hard
AUTHOR
Mike Oakes, May 18 2001, May 19 2001
STATUS
approved