%I

%S 0,5,4,0,14,7,20,11,10,273,14,13,38,89,68,0

%N Numbers k such that A122735(n) = n^k - k^n.

%C A122735(n) = {1, 7, 17, 1, 6102977801, 162287, 79792265017612001, ...} Smallest prime of the form (n^k - k^n) for k>1, or 1 if such prime does not exist. Currently a(n) is not known for n = {17,18,22,25,26,27,28,...}.

%Y Cf. A122735.

%K hard,more,nonn

%O 1,2

%A _Alexander Adamchuk_, Mar 05 2007