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 A189667 #6 Mar 30 2012 18:57:25 %S A189667 0,1,1,1,1,2,2,3,3,3,4,4,4,5,5,5,5,6,6,7,7,7,7,8,8,9,9,9,10,10,10,10, %T A189667 11,11,12,12,12,13,13,13,13,14,14,15,15,15,16,16,16,17,17,17,17,18,18, %U A189667 19,19,19,19,20,20,21,21,21,22,22,22,23,23,23,23,24,24,25,25,25,25,26,26,27,27,27 %N A189667 Partial sums of A189664. %C A189667 See A189664. %F A189667 s(n)=[(n+1)/3]-s([(n+1)/3])+s([n/3]), where s(0)=0. %t A189667 (See A189664.) %Y A189667 Cf. A189664, A189665, A189666. %K A189667 nonn %O A189667 1,6 %A A189667 _Clark Kimberling_, Apr 25 2011