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 A341194 #8 Feb 09 2021 11:01:45 %S A341194 1,2,4,3,6,12,5,10,20,13,25,9,17,34,29,57,114,41,81,49,97,33,65,129, %T A341194 113,225,449,169,337,201,401,801,285,545,489,925,1833,641,1281,769, %U A341194 1537,513,1025,2049,1793,3585,1473,2689,1665,3201,6401,2557,4381,3753,7505 %N A341194 a(n) is the least k such that A340873(k) = n. %H A341194 Rémy Sigrist, <a href="/A341194/a341194.png">Illustration of initial terms</a> %H A341194 Rémy Sigrist, <a href="/A341194/a341194.txt">C program for A341194</a> %H A341194 <a href="/index/3#3x1">Index entries for sequences related to 3x+1 (or Collatz) problem</a> %F A341194 a(n) <= 2^n. %F A341194 a(n+1) <= 2*a(n). %e A341194 See Illustration in Links section. %o A341194 (C) See Links section. %Y A341194 Cf. A033491, A340873. %K A341194 nonn,base %O A341194 0,2 %A A341194 _Rémy Sigrist_, Feb 06 2021