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 A036121 #40 Jul 08 2025 21:35:07
%S A036121 1,5,2,10,4,20,8,17,16,11,9,22,18,21,13,19,3,15,6,7,12,14,1,5,2,10,4,
%T A036121 20,8,17,16,11,9,22,18,21,13,19,3,15,6,7,12,14,1,5,2,10,4,20,8,17,16,
%U A036121 11,9,22,18,21,13,19,3,15,6,7,12,14,1,5,2,10,4,20,8
%N A036121 5^n mod 23.
%D A036121 I. M. Vinogradov, Elements of Number Theory, pp. 220 ff.
%H A036121 Vincenzo Librandi, <a href="/A036121/b036121.txt">Table of n, a(n) for n = 0..1000</a>
%H A036121 <a href="/index/Rec#order_12">Index entries for linear recurrences with constant coefficients</a>, signature (1, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1).
%F A036121 a(n) = +a(n-1) -a(n-11) +a(n-12). G.f.: ( -1-4*x+3*x^2-8*x^3+6*x^4-16*x^5+12*x^6-9*x^7+x^8+5*x^9+2*x^10-14*x^11 ) / ( (x-1)*(1+x)*(x^10-x^9+x^8-x^7+x^6-x^5+x^4-x^3+x^2-x+1) ). - _R. J. Mathar_, Apr 20 2010
%F A036121 a(n) = a(n+22). - _R. J. Mathar_, Jun 04 2016
%p A036121 with(numtheory): i=9: [ seq(primroot(ithprime(i))^j mod ithprime(i), j=0..100) ];
%t A036121 Mod[5^Range[0, 50], 23] (* _Wesley Ivan Hurt_, Jul 06 2014 *)
%t A036121 PowerMod[5,Range[0,80],23] (* or *) PadRight[{},80,{1,5,2,10,4,20,8,17,16,11,9,22,18,21,13,19,3,15,6,7,12,14}] (* _Harvey P. Dale_, Jul 10 2018 *)
%o A036121 (Sage) [power_mod(5,n,23)for n in range(0,63)] # - _Zerinvary Lajos_, Nov 26 2009
%o A036121 (Magma) [Modexp(5, n, 23): n in [0..100]]; // _Vincenzo Librandi_, Feb 07 2011
%o A036121 (PARI) a(n)=lift(Mod(5,23)^n) \\ _Charles R Greathouse IV_, Mar 22 2016
%K A036121 nonn,easy
%O A036121 0,2
%A A036121 _N. J. A. Sloane_