A249623 - OEIS

%I #15 Aug 13 2020 22:16:01

%S 2,3,4,15,8,7,0,347,0,11,3682,17,0,23,0,17,26,313,30,47,400,53,1428,0,

%T 0,77,214,195,3820,709,270,7653,956,9495,0,65,396,905,0,737,0,73,0,0,

%U 1712,0,0,0,0,0,0,167,0,383,0,0,110,0,100,0,0,3435,2806,0,92,1729,84,0,0,0,122,173,3792,0,514,0,0,163,0,101,0,195,438,277,0,369,6392,0,294,0,0,0,122,137,6326,0,0,0,116

%N Conjectured least number k such that k^k - n^n is prime.

%C The zero entries are only conjectural.

%C a(7) > 15000 or 0. Other a(n) = 0 entries have been checked up to k = 10^4. - _Jinyuan Wang_, Aug 09 2020

%o (PARI) a(n)=k=1;while(k<7500,if(ispseudoprime(k^k-n^n),return(k));k++)

%Y Cf. A249570.

%K nonn,hard,more

%O 1,1

%A _Derek Orr_, Nov 02 2014

%E a(32) and a(34) corrected by _Jinyuan Wang_, Aug 13 2020