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 A230643 #10 Nov 01 2013 14:11:34 %S A230643 1,1,2,1,2,2,2,2,1,2,2,2,2,1,3,2,3,1,2,2,2,2,1,2,2,2,2,1,3,2,3,1,2,2, %T A230643 2,2,1,2,2,2,2,2,3,3,2,2,2,2,2,1,2,2,2,2,1,3,2,3,1,2,2,2,2,1,2,2,2,2, %U A230643 1,3,2,3,1,2,2,2,2,1,2,2,2,2,2,3,3,2,2,2,2,2,1,2,2,2,2,1,3,2,3,1,2,2,2 %N A230643 Number of integers m such that m + (sum of digits in base-3 representation of m) = 2n. %C A230643 Number of times 2n appears in A230641. %H A230643 Donovan Johnson, <a href="/A230643/b230643.txt">Table of n, a(n) for n = 0..10000</a> %H A230643 <a href="/index/Coi#Colombian">Index entries for Colombian or self numbers and related sequences</a> %Y A230643 Cf. A230641, A230642. %Y A230643 Related base-3 sequences: A053735, A134451, A230641, A230642, A230643, A230853, A230854, A230855, A230856, A230639, A230640, A010063 (trajectory of 1) %K A230643 nonn,base %O A230643 0,3 %A A230643 _N. J. A. Sloane_, Oct 31 2013