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 A355187 #22 Jul 04 2022 04:38:08
%S A355187 6,89,933,9401,93744,937712,9379078,93773848
%N A355187 Number of Collatz trajectories (A070165) for all positive integers <= 10^n that contain 2^4 as the greatest power of 2 within its trajectory.
%C A355187 It is conjectured that lim_{n->infinity} a(n)/10^n = 15/16. Empirically, 93.75% of all trajectories have 2^4 as the greatest power of 2 within its trajectory. Sequence A135282(n) is the maximum power of 2 reached in the Collatz trajectory for integer n.
%H A355187 <a href="/index/3#3x1">Index entries for sequences related to 3x+1 (or Collatz) problem</a>
%e A355187 a(1)=6 because the first 10 positive integers have trajectories, of which 6 have 2^4 as the greatest power of 2 in their trajectory.
%e A355187 These integers are 3, 5, 6, 7, 9, 10. See trajectory tables below.
%e A355187 1: 1
%e A355187 2: 2 1
%e A355187 3: 3 10 5 16 8 4 2 1
%e A355187 4: 4 2 1
%e A355187 5: 5 16 8 4 2 1
%e A355187 6: 6 3 10 5 16 8 4 2 1
%e A355187 7: 7 22 11 34 17 52 26 13 40 20 10 5 16 8 4 2 1
%e A355187 8: 8 4 2 1
%e A355187 9: 9 28 14 7 22 11 34 17 52 26 13 40 20 10 5 16 8 4 2 1
%e A355187 10: 10 5 16 8 4 2 1
%t A355187 collatz[n_] := Module[{}, If[OddQ[n], 3n+1, n/2]]; step[n_] := Module[{p=0, m=n, q}, While[!IntegerQ[q=Log[2, m]], m=collatz[m]; p++]; {p, q}]; Counts[Table[Last@step[n], {n, 1, 10^5}]][[Key[4]]]
%Y A355187 Cf. A070165, A135282.
%K A355187 nonn,more
%O A355187 1,1
%A A355187 _Frank M Jackson_, Jun 23 2022