A301635 - OEIS

A301635

Numbers k such that 5^k + 5*k + 1 is prime.

0, 1, 11, 25, 35, 85, 499, 1403, 3511, 3739, 8005

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OFFSET

1,3

COMMENTS

a(12), if it exists, is greater than 20000. - Vaclav Kotesovec, Mar 25 2018

a(12), if it exists, is greater than 80000. - Michael S. Branicky, Sep 03 2024

LINKS

MATHEMATICA

Flatten[{0, Select[Range[1000], PrimeQ[5^# + 5*# + 1] &]}] (* Vaclav Kotesovec, Mar 25 2018 *)

PROG

(PARI) for(n=0, 500, if(isprime(5^n+5*n+1), print1(n", ")))

CROSSREFS

A301638 gives the primes.

KEYWORD

nonn,more

AUTHOR

EXTENSIONS

a(8)-a(11) from Vaclav Kotesovec, Mar 25 2018

STATUS

approved