A180740 Numbers k such that 7^k + 5^k + 1 is prime.

0, 1, 11, 731, 3029, 63071

Offset

1,3

Links

Table of n, a(n) for n=1..6.

Prog

(Magma) [n: n in [0..700]|IsPrime(7^n+5^n+1)];
(PARI) is(n)=ispseudoprime(7^n+5^n+1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A267954 A206646 A267908 * A330309 A110776 A058392

Adjacent sequences: A180737 A180738 A180739 * A180741 A180742 A180743

Keyword

nonn,more

Author

Vincenzo Librandi, Jan 22 2011

Extensions

a(4)-a(5) from D. S. McNeil, Jan 24 2011

a(6) from Michael S. Branicky, Oct 11 2024

Status

approved