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 A088570 #10 May 30 2017 00:08:30 %S A088570 1,4,2,2,1,4,1,4,2,2,2,4,1,2,2,2,1,4,2,2,2,2,1,4,1,4,2,2,1,4,1,2,2,2, %T A088570 2,4,1,4,2,2,1,4,1,4,2,2,2,2,1,4,1,2,2,4,1,4,2,2,1,4,1,4,2,2,2,4,1,2, %U A088570 2,2,1,4,1,4,2,2,2,2,1,4,2,2,2,4,1,2,2,2,2,4,1,4,2,2,1,4,1,2,2,4,1,4,1,2,2 %N A088570 Sum of terms in n-th block of Kolakoski sequence. %F A088570 a(n) = (3+(-1)^n)/2*A000002(n). %Y A088570 Cf. A000002. %K A088570 nonn %O A088570 1,2 %A A088570 _Benoit Cloitre_, Nov 17 2003