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 A216097 #21 Sep 08 2022 08:46:03 %S A216097 1,3,9,27,81,243,729,2187,6561,9683,9049,7147,1441,4323,2969,8907, %T A216097 6721,163,489,1467,4401,3203,9609,8827,6481,9443,8329,4987,4961,4883, %U A216097 4649,3947,1841,5523,6569,9707,9121,7363,2089,6267,8801,6403,9209,7627,2881,8643,5929,7787,3361,83,249,747 %N A216097 3^n mod 10000. %C A216097 Period = 500. %H A216097 V. Raman and Vincenzo Librandi, <a href="/A216097/b216097.txt">Table of n, a(n) for n = 0..1000</a> (first 500 terms from V. Raman) %t A216097 PowerMod[3,Range[0,60],10000] (* _Harvey P. Dale_, Oct 18 2015 *) %o A216097 (PARI) for(i=0, 100, print(3^i%10000" ")) %o A216097 (Magma) [Modexp(3, n, 10000): n in [0..110]]; // _Vincenzo Librandi_, Aug 16 2016 %Y A216097 Cf. A001148, A001218, A216096. %K A216097 nonn,easy %O A216097 0,2 %A A216097 _V. Raman_, Sep 01 2012 %E A216097 Definition corrected by _Zak Seidov_, Jul 27 2014 %E A216097 a(0) = 1, offset changed by _Vincenzo Librandi_, Aug 16 2016