A301524 Numbers k such that 16*k^k - 1 is prime.

3, 5, 15, 27

Offset

1,1

Comments

All terms are odd since 16*(2*m)^(2*m) - 1 = (2^(m+2)*m^m - 1)*(2^(m+2)*m^m + 1). - Altug Alkan, Mar 23 2018

a(5), if it exists, is greater than 5000. - Vaclav Kotesovec, Mar 25 2018

a(5), if it exists, is greater than 20000. - Michael S. Branicky, Sep 03 2024

Links

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

Mathematica

Select[Range[1000], PrimeQ[16*#^# - 1] &] (* Vaclav Kotesovec, Mar 25 2018 *)

Prog

(PARI) for(n=0, 1000, if(isprime(16*n^n-1), print1(n", ")))

Crossrefs

Cf. A110931, A301522.

Sequence in context: A146582 A349967 A321985 * A202212 A253790 A372430

Adjacent sequences: A301521 A301522 A301523 * A301525 A301526 A301527

Keyword

nonn,more,changed

Author

Seiichi Manyama, Mar 23 2018

Status

approved