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 A185455 #13 Oct 08 2019 15:04:48 %S A185455 7,18,9,23,58,29,73,183,458,229,573,1433,3583,8958,4479,11198,5599, %T A185455 13998,6999,17498,8749,21873,54683,136708,68354,34177,85443,213608, %U A185455 106804,53402,26701,66753,166883,417208,208604,104302,52151,130378,65189,162973,407433,1018583,2546458,1273229,3183073,7957683,19894208,9947104 %N A185455 Trajectory of 7 under repeated application of the map in A185452. %C A185455 It is conjectured that this trajectory is unbounded, but this is an open problem. %D A185455 J. C. Lagarias, ed., The Ultimate Challenge: The 3x+1 Problem, Amer. Math. Soc., 2010; see page 89. %H A185455 Rémy Sigrist, <a href="/A185455/b185455.txt">Table of n, a(n) for n = 1..10000</a> %H A185455 <a href="/index/3#3x1">Index entries for sequences related to 3x+1 (or Collatz) problem</a> %p A185455 f:=n->if n mod 2 = 0 then n/2 else (5*n+1)/2; fi; %p A185455 T:=proc(n,M) global f; local t1,i; t1:=[n]; %p A185455 for i from 1 to M-1 do t1:=[op(t1),f(t1[nops(t1)])]; od: t1; end; %p A185455 T(7,120); %Y A185455 Cf. A185452, A185453, A185454. %K A185455 nonn %O A185455 1,1 %A A185455 _N. J. A. Sloane_, Feb 04 2011