Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #14 Sep 06 2014 00:24:49
%S 3,7,23,47,283,719,1439,2879,34549,138197,1266767,14619833,36449279,
%T 377982107,1432349099
%N Smallest k such that 9^^n is not congruent to 9^^(n-1) mod k, where 9^^n denotes the power tower 9^9^...^9 (in which 9 appears n times).
%C For general remarks regarding sequences of this type, see A246491.
%C This particular sequence shares all known terms with A082449. they might be identical.
%o (Sage, cython) Use linked source from A246491 with this command: find_k_values(9,1,1)
%Y Cf. A082449, A027763, A246491, A246492, A246493, A246494, A246495, A246496.
%K nonn,more
%O 1,1
%A _Wayne VanWeerthuizen_, Aug 27 2014