A309410 Numbers k such that (41^k + 1)/42 is prime.

17, 691, 113749

Offset

1,1

Comments

Larger terms correspond to probable primes.

Links

Table of n, a(n) for n=1..3.

P. Bourdelais, A Generalized Repunit Conjecture

Mathematica

Do[p=Prime[n]; If[ PrimeQ[(41^p + 1)/42], Print[p]], {n, 1, 1000000}]

Prog

(PARI) is(n)=ispseudoprime((41^n+1)/42)

Crossrefs

Sequence in context: A012157 A012137 A171198 * A201311 A012182 A012029

Adjacent sequences: A309407 A309408 A309409 * A309411 A309412 A309413

Keyword

nonn,bref,hard,more

Author

Paul Bourdelais, Jul 29 2019

Status

approved