This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A036160 #13 Jul 08 2025 21:36:31 %S A036160 1,3,9,27,81,20,60,180,94,59,177,85,32,96,65,195,139,194,136,185,109, %T A036160 104,89,44,132,173,73,219,211,187,115,122,143,206,172,70,210,184,106, %U A036160 95,62,186,112,113,116,125,152,10 %N A036160 a(n) = 3^n mod 223. %D A036160 I. M. Vinogradov, Elements of Number Theory, pp. 220 ff. %p A036160 [ seq(primroot(ithprime(i))^j mod ithprime(i),j=0..100) ]; %t A036160 PowerMod[3,Range[0,50],223] (* _Harvey P. Dale_, Jan 04 2012 *) %o A036160 (PARI) a(n)=lift(Mod(3,223)^n) \\ _Charles R Greathouse IV_, Mar 22 2016 %K A036160 nonn,easy %O A036160 0,2 %A A036160 _N. J. A. Sloane_