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 A171219 #5 Mar 30 2012 18:52:04 %S A171219 5,5,21,21,21,21,21,21,21,21,57,57,57,57,57,57,57,57,57,57,57,57,57, %T A171219 57,57,57,57,57,121,121,121,121,121,121,121,121,121,121,121,121,121, %U A171219 121,121,121,121,121,121,121,121,121,121,121,121,121,121,121,121,121,121 %N A171219 A138101(n)+A168142(n). %C A171219 This here basically repeats entries A168388(2k+1) 2*k^2 times for k=1,2,.... %C A171219 The construction is similar to A168234. %K A171219 nonn,easy,less %O A171219 1,1 %A A171219 _Paul Curtz_, Dec 05 2009 %E A171219 Comments tightened - _R. J. Mathar_, Nov 24 2010