A062639 Numbers k such that 73^k - 72^k is prime.

19, 83, 1091, 20117

Offset: 1

Author

Mike Oakes, May 18 2001, May 19 2001

Keywords

• nonn
• hard

Comments

Terms greater than 1000 are often only strong pseudoprimes.

a(5) > 10^5. - Robert Price, Apr 21 2014

Crossrefs

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

Programs

PARI

is(n)=ispseudoprime(73^n-72^n) \\ Charles R Greathouse IV, Jun 13 2017

Extensions

a(4) from Robert Price, Apr 21 2014 (Computer run by Adam Marciniec)