A062585 Numbers k such that 19^k - 18^k is prime.

2, 1607, 1873, 10957

Offset: 1

Author

Mike Oakes, May 18 2001, May 19 2001

Keywords

• nonn
• hard

Comments

PrimePi[ a(n) ] = {2, 253, 287, 1331, ...}. - Alexander Adamchuk, Feb 16 2007

a(5) > 10^5. - Robert Price, Jun 05 2012

Terms greater than 1000 may correspond to (unproven) strong pseudoprimes. - M. F. Hasler, Sep 16 2013

Crossrefs

Cf. A000043, A057468, A059801, A059802, A062572-A062583, A188051, A062586-A062666.

Programs

PARI

is(n)=ispseudoprime(19^n-18^n) \\ Charles R Greathouse IV, Feb 20 2017

Extensions

10957 (found by Mike Oakes in 2003) from Alexander Adamchuk, Feb 16 2007