A057437 Numbers k such that 10*7^k + 1 is prime.

0, 1, 2, 5, 7, 9, 11, 14, 22, 45, 54, 67, 74, 321, 706, 902, 962, 11393, 13605, 17005, 17364, 27129, 27674, 29447

Offset

1,3

Comments

a(22) > 20169. - Jinyuan Wang, Jan 21 2020

a(25) > 50000. - Michael S. Branicky, Oct 28 2024

Links

Table of n, a(n) for n=1..24.

Mathematica

Do[ If[ PrimeQ[ 10*7^n + 1], Print[n]], {n, 1, 1000}]

Prog

(PARI) is(n)=ispseudoprime(10*7^n+1) \\ Charles R Greathouse IV, Jun 12 2017

Crossrefs

Sequence in context: A169865 A286991 A029905 * A339922 A359071 A196255

Adjacent sequences: A057434 A057435 A057436 * A057438 A057439 A057440

Keyword

nonn,more

Author

Robert G. Wilson v, Sep 08 2000

Extensions

First term 0 inserted by and a(18)-a(21) from Jinyuan Wang, Jan 21 2020

a(22)-a(23) from Michael S. Branicky, Mar 20 2024

a(24) from Michael S. Branicky, Oct 28 2024

Status

approved