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 A069203 #8 Nov 21 2013 12:47:46
%S A069203 0,3,1,4,5,3,8,11,19,10,29,13,14,9,23,32,55,29,28,19,47,22,23,15,38,
%T A069203 53,91,48,139,187,326,171,497,668,1165,611,592,401,331,244,575,273,
%U A069203 848,1121,1969,1030,2999,1343,4342,1895,2079,3974,6053,10027,5360,5129
%N A069203 a(1)=0 a(2)=3 a(n+2)=(a(n+1)+a(n))/3 if (a(n+1)+a(n)==0 (mod 3)); a(n+2)=a(n+1)+a(n) otherwise.
%C A069203 A Collatz-Fibonacci mixture. If a(1)=0 and a(2)=m not congruent to 3, a(n) is cyclic (m,m,2m). Does this sequence diverge to infinity if a(1)=0 and a(2)=m == 0 (mod 3)?
%H A069203 Harvey P. Dale, <a href="/A069203/b069203.txt">Table of n, a(n) for n = 1..1000</a>
%t A069203 Transpose[NestList[{Last[#],If[Divisible[Total[#],3],Total[#]/3, Total[ #]]}&,{0,3},60]][[1]] (* _Harvey P. Dale_, Dec 08 2011 *)
%K A069203 easy,nonn
%O A069203 1,2
%A A069203 _Benoit Cloitre_, Apr 11 2002