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 A186109 #11 Jan 15 2022 21:33:06
%S A186109 1,3,13,7,115,237,15,1935,7825,31473,31711,254649,15957,2050541,
%T A186109 8219801,16490635,33035745,132455435,530485275,1061920785,4253619813,
%U A186109 4256987887,34095896991,136471574881,273072139013,136638599097,2187167322891,4377196161075,4378797345767,35049397190341
%N A186109 Numerator of the cumulative frequency of the dropping time in the Collatz iteration.
%C A186109 The possible dropping times are in A020914. The denominators are in A186110. The frequency of the n-th dropping time is A186107(n)/A186108(n).
%C A186109 Riho Terras' classic paper about the Collatz problem shows the decimal values of 2(1-c(k)) in Table A, where c(k) is the cumulative frequency of dropping times <= k.
%H A186109 <a href="/index/3#3x1">Index entries for sequences related to 3x+1 (or Collatz) problem</a>
%H A186109 Riho Terras, <a href="http://matwbn.icm.edu.pl/ksiazki/aa/aa30/aa3034.pdf">A stopping time problem on the positive integers</a>, ACTA Arith. 30 (1976), 241-252.
%F A186109 a(n) = numerator of Sum_{k=1..n} A186009(k) / 2^A020914(k-1).
%e A186109 The cumulative frequencies are 1/2, 3/4, 13/16, 7/8, 115/128, 237/256, 15/16, 1935/2048, 7825/8192, ... .
%Y A186109 Cf. A126241 (dropping times).
%K A186109 nonn,frac
%O A186109 1,2
%A A186109 _T. D. Noe_, Feb 12 2011