%I #8 Sep 06 2014 00:19:54
%S 2,4,13,47,107,643,1439,2879,34549,138197,858239,2029439,36449279
%N Smallest k such that 6^^n is not congruent to 6^^(n-1) mod k, where 6^^n denotes the power tower 6^6^...^6 (in which 6 appears n times).
%C For general remarks regarding sequences of this type, see A246491.
%o (Sage, cython) Use linked source from A246491 with this command: find_k_values(6,1,1)
%Y Cf. A027763, A246491, A246492, A246493, A246495, A246496, A246497
%K nonn,more
%O 1,1
%A _Wayne VanWeerthuizen_, Aug 27 2014