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 A006885 M2086 #53 Jan 13 2025 06:34:29
%S A006885 1,2,16,52,160,9232,13120,39364,41524,250504,1276936,6810136,8153620,
%T A006885 27114424,50143264,106358020,121012864,593279152,1570824736,
%U A006885 2482111348,2798323360,17202377752,24648077896,52483285312,56991483520,90239155648,139646736808
%N A006885 Record highest point of trajectory before reaching 1 in '3x+1' problem, corresponding to starting values in A006884.
%C A006885 Both the 3x+1 steps and the halving steps are counted.
%C A006885 Record values in A025586: a(n) = A025586(A006884(n)) and A025586(m) < a(n) for m < A006884(n). - _Reinhard Zumkeller_, May 11 2013
%C A006885 In an email of Aug 06 2023, Guy Chouraqui observes that the digital root of a(n) appears to be 7 for all n > 2. - _N. J. A. Sloane_, Aug 11 2023
%D A006885 R. B. Banks, Slicing Pizzas, Racing Turtles and Further Adventures in Applied Mathematics, Princeton Univ. Press, 1999. See p. 96.
%D A006885 D. R. Hofstadter, Goedel, Escher, Bach: an Eternal Golden Braid, Random House, 1980, p. 400.
%D A006885 G. T. Leavens and M. Vermeulen, 3x+1 search problems, Computers and Mathematics with Applications, 24 (1992), 79-99.
%D A006885 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A006885 Hugo Pfoertner, <a href="/A006885/b006885.txt">Table of n, a(n) for n = 1..97</a>, using data from Eric Rosendaal's 3x+1 Path records (terms 1..84 from T. D. Noe)
%H A006885 Brian Hayes, <a href="https://www.jstor.org/stable/24969271">Computer Recreations: On the ups and downs of hailstone numbers</a>, Scientific American, 250 (No. 1, 1984), pp. 10-16.
%H A006885 J. C. Lagarias, <a href="http://www.cecm.sfu.ca/organics/papers/lagarias/paper/html/paper.html">The 3x+1 problem and its generalizations</a>, Amer. Math. Monthly, 92 (1985), 3-23.
%H A006885 G. T. Leavens and M. Vermeulen, <a href="/A006877/a006877_1.pdf">3x+1 search programs</a>, Computers and Mathematics with Applications, 24 (1992), 79-99. (Annotated scanned copy)
%H A006885 Peter Munn, <a href="https://oeis.org/plot2a?name1=A006884&name2=A006885&tform1=log+base+10&tform2=log+base+10&shift=0&radiop1=xy&drawpoints=true&drawlines=true">Plot2 graph of record highest point against starting value</a>
%H A006885 Eric Roosendaal, <a href="http://www.ericr.nl/wondrous/pathrecs.html">3x+1 Path Records</a>
%H A006885 Robert G. Wilson v, <a href="/A006877/a006877.pdf">Letter to N. J. A. Sloane with attachments, Jan. 1989</a>
%H A006885 Robert G. Wilson v, <a href="/A006884/a006884.pdf">Tables of A6877, A6884, A6885, Jan. 1989</a>
%H A006885 <a href="/index/Go#GEB">Index entries for sequences from "Goedel, Escher, Bach"</a>
%H A006885 <a href="/index/3#3x1">Index entries for sequences related to 3x+1 (or Collatz) problem</a>
%t A006885 mcoll[n_]:=Max@@NestWhileList[If[EvenQ[#],#/2,3#+1]&,n,#>=n&]; t={1,max=2}; Do[If[(y=mcoll[n])>max,AppendTo[t,max=y]],{n,3,10^6,4}]; t (* _Jayanta Basu_, May 28 2013 *)
%o A006885 (Haskell)
%o A006885 a006885 = a025586 . a006884 -- _Reinhard Zumkeller_, May 11 2013
%Y A006885 Cf. A006884, A006877, A006878, A033492.
%K A006885 nonn,nice
%O A006885 1,2
%A A006885 _Robert Munafo_