%I A125774
%S A125774 1,2,3,4,9,11,20,22,27,33,81,99,220,243,644,729,1220,2187,2420,5060,
%T A125774 6561,7128,8368,13420,14740,19683,23620,40573,55660,59049,145420,147620,
%U A125774 162140,177147,237820,259820,290620,308660,339020,447740,531441,548660
%N A125774 Numbers n such that 3^n (mod n) = 3^n (mod n^2).
%C A125774 a(n) includes all powers of 3. a(2) = 2, a(3) = 3, a(6) = 11 and a(45) 
               = 1006003 are the only known primes in a(n).
%t A125774 Do[f=PowerMod[3,n,n];g=PowerMod[3,n,n^2];If[f==g,Print[n]],{n,1,1100000}]
%Y A125774 Cf. A014127 = Primes p such that p^2 divides 3^(p-1) - 1. Cf. A068535 
               = numbers n such that 2^n (mod n) = 2^n (mod n^2). Cf. A125773 = 
               numbers n, that are not the powers of 2, such that 2^n (mod n) = 
               2^n (mod n^2). Cf. A125775 = numbers n such that 5^n (mod n) = 5^n 
               (mod n^2).
%Y A125774 Sequence in context: A118223 A093514 A080231 this_sequence A062410 A145772 
               A027866
%Y A125774 Adjacent sequences: A125771 A125772 A125773 this_sequence A125775 A125776 
               A125777
%K A125774 nonn
%O A125774 1,2
%A A125774 Alexander Adamchuk (alex(AT)kolmogorov.com), Dec 07 2006