A062635 Numbers k such that 69^k - 68^k is prime.

2, 17, 1543, 83653

Offset: 1

Author

Mike Oakes, May 18 2001, May 19 2001

Keywords

• nonn
• hard
• bref

Comments

Terms greater than 1000 are often only strong pseudoprimes.

a(5) > 10^5. - Robert Price, Dec 16 2013

Crossrefs

Cf. A000043, A057468, A059801, A059802, A062572-A062666.

Programs

PARI

is(n)=ispseudoprime(69^n-68^n) \\ Charles R Greathouse IV, Jun 13 2017

Extensions

a(4) from Robert Price, Dec 16 2013 (Computer run by Adam Marciniec)