%I #2 Mar 31 2012 13:20:28
%S 1,52,124,431
%N Numbers n such that 1 + Sum k^k (k=1..n) is prime.
%C Primes of the form A001923[n] = Sum k^k (k=1..n) are given in A073826[n] and their indices are given in A073825[n] = {2,5,6,10,30,...}.
%t s=1; Do[s=s+k^k;If[PrimeQ[s],Print[{k,s}]],{k,1,500}]
%Y Cf. A073825, A001923.
%K nonn
%O 1,2
%A _Alexander Adamchuk_, Aug 23 2006