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).

A246497

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).

Terms

    a(0) =3a(1) =7a(2) =23a(3) =47a(4) =283a(5) =719a(6) =1439a(7) =2879a(8) =34549a(9) =138197a(10) =1266767a(11) =14619833a(12) =36449279a(13) =377982107a(14) =1432349099

External references