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 A119397 #3 Mar 30 2012 17:26:21 %S A119397 71820,103950,127764,135660,141360,161460,173250,183744,193284,203580, %T A119397 206712,209440,214830,217620,221760,223020,223860,234432,243540, %U A119397 244440,246330,247752,256680,263160,264180,265200,280368,281160,286380,287712 %N A119397 Numbers taking exactly 21 steps to reach 15 in A086793. %C A119397 Some trajectories are: 71820,1104,168,102,36,46,18,30,27,22,9,13,5,6,12,19,11,3,4,7,8,15 103950,1134,168,... 127764,924,168,... 135660,1134,168,... 221760,1908,162,66,36,... 343728,1650,162,... 376992,2016,297,66,36,... All trajectories eventually join one of previous trajectories. In the first 136 terms <800000 there is only one odd number, 628425. Next odd terms are: 824175, 1340325, 1422135, 1495725 (see A119398). %Y A119397 Cf. A086793, A119396-A119415. %K A119397 base,nonn %O A119397 1,1 %A A119397 _Zak Seidov_, May 18 2006