A108468 Numbers k such that (1/9)*(-1 + 10^k) + k is prime.

1, 2, 8, 10, 20, 590, 1058

Offset

1,2

Comments

Some of the larger entries may only correspond to probable primes.

a(8) > 6000. - Tyler NeSmith, May 09 2021

a(8) > 10^5. - Michael S. Branicky, Sep 27 2024

Links

Table of n, a(n) for n=1..7.

Prog

(PARI) is(n)=ispseudoprime((10^n-1)/9+n) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Cf. A110369.

Sequence in context: A032356 A114272 A193266 * A165593 A127219 A122208

Adjacent sequences: A108465 A108466 A108467 * A108469 A108470 A108471

Keyword

more,nonn

Author

Jason Earls, Jul 25 2005

Status

approved