A301524 - OEIS

%I #19 Sep 03 2024 17:19:36

%S 3,5,15,27

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

%C 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

%C a(5), if it exists, is greater than 5000. - _Vaclav Kotesovec_, Mar 25 2018

%C a(5), if it exists, is greater than 20000. - _Michael S. Branicky_, Sep 03 2024

%t Select[Range[1000], PrimeQ[16*#^# - 1] &] (* _Vaclav Kotesovec_, Mar 25 2018 *)

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

%Y Cf. A110931, A301522.

%K nonn,more

%O 1,1

%A _Seiichi Manyama_, Mar 23 2018