A171227 Numbers k such that 9 + 10^k + 9*100^k is prime.

0, 1, 4, 17, 26, 28, 47, 70, 91, 1129, 4334, 12347

Offset

1,3

Comments

No more terms up to k = 4100.

Links

Table of n, a(n) for n=1..12.

Example

19, 919, 900010009 are prime so that 0, 1 and 4 are terms.

Prog

(PARI) is(n)=ispseudoprime(9+10^n+9*100^n) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Cf. A083816.

Sequence in context: A273022 A273119 A302618 * A061387 A366210 A335593

Adjacent sequences: A171224 A171225 A171226 * A171228 A171229 A171230

Keyword

more,nonn

Author

Jason Earls, Dec 05 2009

Extensions

a(11)-a(12) from Michael S. Branicky, Jun 22 2023

Status

approved