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 A066756 #17 May 25 2022 02:26:09 %S A066756 1,2,6,65,673,342,2919,129991,1590511,301695657,1412987847 %N A066756 Smallest number that requires n^3 steps to reach 1 in its Collatz trajectory (counting x/2 and 3x+1 steps). %C A066756 a(11) > 7*10^11. - _Donovan Johnson_ %D A066756 R. K. Guy, Problem E16, Unsolved Problems in Number Theory, 2nd edition, Springer-Verlag, NY pp. 215-218 %H A066756 <a href="/index/3#3x1">Index entries for sequences related to 3x+1 (or Collatz) problem</a> %F A066756 Mapping at each step for Collatz problem: x -> x/2 if n is even, else x -> 3*x+1; count the steps until x=1. %e A066756 a(2) = 6 since the trajectory of 6 requires 2^3 = 8 steps to reach 1 (the trajectory is 6 -> 3 -> 10 -> 5 -> 16 -> 8 -> 4 -> 2 -> 1), and 6 is the smallest number for which this is the case. %Y A066756 Cf. A006577, A066773. %K A066756 nonn,more %O A066756 0,2 %A A066756 _Randall L Rathbun_, Jan 18 2002 %E A066756 More terms from Larry Reeves (larryr(AT)acm.org), Apr 12 2002 %E A066756 a(10) from _Donovan Johnson_, Nov 13 2010 %E A066756 Edited by _Jon E. Schoenfield_, Jan 28 2014