login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A309409 Numbers k such that (37^k + 1)/38 is prime. 0
5, 7, 2707, 163193 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Larger terms correspond to probable primes.

LINKS

Table of n, a(n) for n=1..4.

P. Bourdelais, A Generalized Repunit Conjecture

MATHEMATICA

Do[p=Prime[n]; If[PrimeQ[(37^p + 1)/38], Print[p]], {n, 1, 1000000}]

PROG

(PARI) is(n)=ispseudoprime((37^n+1)/38)

CROSSREFS

Sequence in context: A056252 A274774 A176599 * A291687 A257774 A281386

Adjacent sequences:  A309406 A309407 A309408 * A309410 A309411 A309412

KEYWORD

nonn,hard,more

AUTHOR

Paul Bourdelais, Jul 29 2019

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 23 06:38 EDT 2021. Contains 343201 sequences. (Running on oeis4.)