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 A065366 #2 Mar 30 2012 17:38:10 %S A065366 1,-3,-2,-1,5,6,7,3,4,5,1,2,3,-11,-10,-9,-13,-12,-11,-15,-14,-13,-7, %T A065366 -6,-5,-9,-8,-7,-11,-10,-9,-3,-2,-1,-5,-4,-3,-7,-6,-5,21,22,23,19,20, %U A065366 21,17,18,19,25,26,27,23,24,25,21,22,23,29,30,31,27,28,29,25,26,27,13,14,15,11,12,13,9,10,11,17,18,19,15 %N A065366 Replace 3^k with (-2)^k in balanced ternary expansion of n. %C A065366 Notation: (3)< n >(2) %e A065366 5 = +1(9)-1(3)-1(1) -> +1(4)-1(-2)-1(1) = 5 = a(5) %Y A065366 A065364, A065365 %K A065366 base,easy,sign %O A065366 1,2 %A A065366 _Marc LeBrun_, Oct 31 2001