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 A143591 #2 Mar 30 2012 18:57:10 %S A143591 1,0,2,1,2,1,4,4,8,12,18,28,40,60,91,134,203,302,455,681,1019,1535, %T A143591 2292,3447,5157,7759,11617,17458,26172,39270,58888,88328,132483, %U A143591 198711,298005,447096,670645,1005943,1509029,2263285 %N A143591 Number of 1's in row n of A143589 (a Kolakoski fan). %C A143591 A143590 = A143591 + A143592. %e A143591 The first 6 rows of A143589 are 1; 2; 1,1; 2,1; 1,1,2; 2,1,2,2. The %e A143591 respective numbers of 1's are 1,0,2,1,2,1. %Y A143591 Cf. A000002, A143587, A143589, A143590, A143592. %K A143591 nonn %O A143591 1,3 %A A143591 _Clark Kimberling_, Aug 25 2008