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 A070517 #22 Dec 18 2023 16:15:38 %S A070517 0,1,3,3,9,1,9,9,1,9,3,3,1,0,1,3,3,9,1,9,9,1,9,3,3,1,0,1,3,3,9,1,9,9, %T A070517 1,9,3,3,1,0,1,3,3,9,1,9,9,1,9,3,3,1,0,1,3,3,9,1,9,9,1,9,3,3,1,0,1,3, %U A070517 3,9,1,9,9,1,9,3,3,1,0,1,3,3,9,1,9,9,1,9,3,3,1,0,1,3,3,9,1,9,9,1,9 %N A070517 a(n) = n^4 mod 13. %C A070517 Equivalently: n^(12*m + 4) mod 13. - _G. C. Greubel_, Apr 01 2016 %H A070517 <a href="/index/Rec#order_13">Index entries for linear recurrences with constant coefficients</a>, signature (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1). %F A070517 From _G. C. Greubel_, Apr 01 2016: (Start) %F A070517 a(n+13) = a(n). %F A070517 a(13*m) = 0. %F A070517 G.f.: (x +3*x^2 +3*x^3 +9*x^4 +x^5 +9*x^6 +9*x^7 +x^8 +9*x^9 +3*x^10 +3*x^11 +x^12)/(1 - x^13). (End) %t A070517 PowerMod[Range[0, 100], 4, 13] (* _G. C. Greubel_, Apr 01 2016 *) %o A070517 (Sage) [power_mod(n,4,13)for n in range(0, 101)] # _Zerinvary Lajos_, Oct 31 2009 %o A070517 (Magma) [Modexp(n, 4, 13): n in [0..100]]; // _Vincenzo Librandi_, Apr 02 2016 - after _Bruno Berselli_ in A070403. %o A070517 (PARI) a(n)=n^4%13 \\ _Charles R Greathouse IV_, Apr 06 2016 %K A070517 nonn,easy %O A070517 0,3 %A A070517 _N. J. A. Sloane_, May 13 2002