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 A082656 #5 Apr 07 2020 03:40:09 %S A082656 39,126,63,198,99,306,153,468,234,117,360,180,90,45,144,72,36,18,9,36, %T A082656 18,9,36,18,9,36,18,9,36,18,9,36,18,9,36,18,9,36,18,9,36,18,9,36,18,9, %U A082656 36,18,9,36,18,9,36,18,9,36,18,9,36,18,9,36,18,9,36,18,9 %N A082656 Trajectory of 39 under map x -> x/2 if x even, 3x+9 if x odd. %Y A082656 Cf. A067896. %K A082656 nonn %O A082656 1,1 %A A082656 _Ernst Berg_, May 17 2003 %E A082656 More terms from _Jinyuan Wang_, Apr 07 2020