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 A143592 #2 Mar 30 2012 18:57:10 %S A143592 0,1,0,1,1,3,3,6,8,12,18,26,40,60,89,135,201,303,453,680,1022,1528, %T A143592 2299,3443,5176,7750,11642,17443,26172,39246,58874,88308,132461, %U A143592 198694,298094,447097,670645,1005992,1508898,2263540 %N A143592 Number of 2's in row n of A143589 (a Kolakoski fan). %C A143592 A143590 = A143591 + A143592. %e A143592 The first 6 rows of A143589 are 1; 2; 1,1; 2,1; 1,1,2; 2,1,2,2. The %e A143592 respective numbers of 1's are 0,1,0,1,1,3. %Y A143592 Cf. A000002, A143587, A143589, A143590, A143591. %K A143592 nonn %O A143592 1,6 %A A143592 _Clark Kimberling_, Aug 25 2008