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 A223699 #4 Mar 26 2013 12:19:28
%S A223699 1,2,4,8,3,32,21,20,13,80,15,7,96,69,68,45,93,19,61,56,37,51,72,49,39,
%T A223699 33,43,133,79,260,115,349,255,127,27,157,135,279,123,421,375,727,219,
%U A223699 723,447,295,740,493,439,591,657,1281,1159,877,759,615,519,1603
%N A223699 Least number whose Collatz (3x+1) iteration has its maximum value at position n (counting from 1).
%C A223699 The maximum values are in A223700.
%H A223699 T. D. Noe, <a href="/A223699/b223699.txt">Table of n, a(n) for n = 1..800</a>
%e A223699 The Collatz iteration of 15 is {15, 46, 23, 70, 35, 106, 53, 160, 80, 40, 20, 10, 5, 16, 8, 4, 2, 1}. The maximum is 160, which occurs at position 11, counting from the right. Hence, a(11) = 15 because no number smaller than 15 has its maximum value at the 11 position.
%t A223699 Collatz[n_] := NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, n, # > 1 &]; t= Table[c = Reverse[Collatz[n]]; Position[c, Max[c]][[1, 1]], {n, 10000}]; t2 = {}; n = 0; While[n++; p = Position[t, n, 1, 1]; p != {}, AppendTo[t2, p[[1,1]]]]; t2
%Y A223699 Cf. A070165 (Collatz iteration of n), A223700.
%K A223699 nonn
%O A223699 1,2
%A A223699 _T. D. Noe_, Mar 26 2013