A301635 Numbers k such that 5^k + 5*k + 1 is prime.

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

Offset

1,3

Comments

Next term, if it exists, is greater than 20000. - Vaclav Kotesovec, Mar 25 2018

Links

Table of n, a(n) for n=1..11.

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.

Cf. A171058, A301634.

Sequence in context: A286279 A125868 A240895 * A031025 A140675 A161532

Adjacent sequences: A301632 A301633 A301634 * A301636 A301637 A301638

Keyword

nonn,more

Author

Seiichi Manyama, Mar 25 2018

Extensions

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

Status

approved