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 A216131 #12 Sep 08 2022 08:46:03 %S A216131 1,11,121,331,641,51,561,171,881,691,601,611,721,931,241,651,161,771, %T A216131 481,291,201,211,321,531,841,251,761,371,81,891,801,811,921,131,441, %U A216131 851,361,971,681,491,401,411,521,731,41,451,961,571,281,91,1,11,121,331,641,51,561,171,881,691,601 %N A216131 a(n) = 11^n mod 1000. %C A216131 Period = 50. %H A216131 Vincenzo Librandi, <a href="/A216131/b216131.txt">Table of n, a(n) for n = 0..1000</a> %t A216131 PowerMod[11, Range[0, 100], 1000] (* _Vincenzo Librandi_, Aug 16 2016 *) %o A216131 (PARI) for(i=0, 100, print(11^i%1000" ")) %o A216131 (Magma) [Modexp(11, n, 1000): n in [0..110]]; // _Vincenzo Librandi_, Aug 16 2016 %Y A216131 Cf. A216100. %K A216131 nonn,easy %O A216131 0,2 %A A216131 _V. Raman_, Sep 01 2012 %E A216131 a(0) = 1 prepended and offset changed by _Vincenzo Librandi_, Aug 16 2016