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 A189631 #6 Mar 30 2012 18:57:24 %S A189631 0,0,1,1,1,2,2,3,3,3,3,4,4,4,5,5,6,6,6,6,7,7,8,8,8,8,9,9,9,10,10,10, %T A189631 11,11,12,12,12,12,13,13,13,14,14,15,15,15,15,16,16,17,17,17,17,18,18, %U A189631 18,19,19,19,20,20,21,21,21,21,22,22,23,23,23,23,24,24,24,25,25,25,26,26,27,27,27 %N A189631 Partial sums of A189628. %C A189631 See A189628. %F A189631 s(n)=[n/3]+s([(n+1)/3])-s([n/3]), where s(0)=0. %t A189631 (See A189638.) %Y A189631 Cf. A189628, A189629, A189630. %K A189631 nonn %O A189631 1,6 %A A189631 _Clark Kimberling_, Apr 24 2011