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 A214211 #8 Apr 28 2020 09:21:37 %S A214211 1,1,2,2,1,1,1,1,2,2,1,1,2,2,1,1,1,1,2,2,1,1,1,1,2,2,1,1,2,2,1,1,1,1, %T A214211 2,2,1,1,2,2,1,1,1,1,2,2,1,1,1,1,2,2,1,1,2,2,1,1,1,1,2,2,1,1,1,1,2,2, %U A214211 1,1,2,2,1,1,1,1,2,2,1,1,2,2,1,1,1,1,2,2,1,1,1,1,2,2,1,1,2,2,1,1,1,1,2,2,1,1,2,2,1,1,1,1,2,2,1,1,1,1,2,2,1,1,2,2,1,1,1,1,2,2,1,1,1,1,2,2,1,1,2,2,1,1,1,1,2,2,1,1,2,2,1,1,1,1,2,2,1,1,1,1,2,2,1,1,2,2,1,1,1,1,2,2,1,1,1,1,2,2,1,1,2,2,1,1,1,1,2,2,1,1,2 %N A214211 Doubled Fibonacci word: the A003842 sequence replacing 1 with 1,1 and 2 with 2,2. %C A214211 Suggested by reading Mignosi et al. (2002). %H A214211 F. Mignosi, A. Restivo, M. Sciortino, <a href="http://dx.doi.org/10.1016/S0304-3975(00)00436-9">Words and forbidden factors</a>, WORDS (Rouen, 1999). Theoret. Comput. Sci. 273 (2002), no. 1-2, 99--117. MR1872445 (2002m:68096). %Y A214211 Cf. A003842, A095190. %K A214211 nonn %O A214211 0,3 %A A214211 _N. J. A. Sloane_, Jul 10 2012