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%I #9 Mar 22 2016 00:59:39
%S 1,19,170,174,59,166,98,143,43,53,52,33,54,71,12,37,130,178,135,82,30,
%T 188,134,63,51,14,75,88,144,62,32,35,92,29,169,155,80,183,39,168,136,
%U 101,9,171,2,38,149,157,118,141
%N 19^n mod 191.
%D I. M. Vinogradov, Elements of Number Theory, pp. 220 ff.
%p [ seq(primroot(ithprime(i))^j mod ithprime(i),j=0..100) ];
%t PowerMod[19,Range[0,50],191] (* _Harvey P. Dale_, Aug 31 2011 *)
%o (PARI) a(n)=lift(Mod(19,191)^n) \\ _Charles R Greathouse IV_, Mar 22 2016
%K nonn,easy
%O 0,2
%A _N. J. A. Sloane_.