A169602 Numbers k such that (10^k-1)^2 + 2 is prime.

0, 1, 2, 4, 5, 17, 18, 23, 57, 58, 340, 837, 4280, 5352, 13675, 17515, 25856

Offset

1,3

Comments

No more terms up to k = 4000.

Links

Table of n, a(n) for n=1..17.

Prog

(PARI) is(n)=ispseudoprime((10^n-1)^2+2) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A038757 A377142 A062549 * A092051 A065063 A276311

Adjacent sequences: A169599 A169600 A169601 * A169603 A169604 A169605

Keyword

more,nonn

Author

Jason Earls, Dec 03 2009

Extensions

a(13)-a(14) from Michael S. Branicky, Jun 21 2023

Offset changed by Andrew Howroyd, Sep 18 2024

a(15)-a(17) from Michael S. Branicky, Sep 20 2024

Status

approved