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

2, 1607, 1873, 10957

Offset

1,1

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

Links

Table of n, a(n) for n=1..4.

Prog

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

Crossrefs

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

Sequence in context: A296362 A282999 A201242 * A239505 A002490 A179961

Adjacent sequences: A062582 A062583 A062584 * A062586 A062587 A062588

Keyword

nonn,hard

Author

Mike Oakes, May 18 2001, May 19 2001

Extensions

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

Status

approved