A224470 Numbers k such that 7^k - k is prime.

2, 6, 8, 12, 44, 48, 512, 1088, 1104, 6038

Offset

1,1

Comments

a(11) > 92000. - Giovanni Resta, Apr 08 2013

a(11) > 2*10^5. - Robert Price, Feb 11 2014

Links

Table of n, a(n) for n=1..10.

Prog

(PARI) forstep(n=2, 10^4, 2, if(ispseudoprime(7^n-n), print1(n, ", "))); /* Joerg Arndt, Apr 07 2013 */

Crossrefs

Cf. A048744, A058037, A057908, A058046, A058829, A224468.

Sequence in context: A030457 A296300 A358970 * A168247 A229056 A186703

Adjacent sequences: A224467 A224468 A224469 * A224471 A224472 A224473

Keyword

nonn,more,changed

Author

Alex Ratushnyak, Apr 06 2013

Status

approved