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 A181762 #52 Mar 08 2024 01:14:27
%S A181762 0,8,1,14,2,20,3,26,4,32,5,38,6,44,7,50,8,56,9,62,10,68,11,74,12,80,
%T A181762 13,86,14,92,15,98,16,104,17,110,18,116,19,122,20,128,21,134,22,140,
%U A181762 23,146,24,152,25,158,26,164,27,170,28,176,29,182,30,188,31,194,32,200,33,206,34,212,35,218,36,224,37
%N A181762 a(n) = n/2 if n is even, otherwise 3n+5.
%C A181762 Has at least two periodic orbits, {1,8,4,2} and {5,20,10}.
%C A181762 Four others are {19,62,31,98,49,152,76,38}, {23,74,37,116,58,29,92,46}, {187,...} and {347,...}. The last two are each of length 44, peaking with 8324 and 10196 respectively. - _Geoffrey H. Morley_, Mar 14 2013
%D A181762 J. C. Lagarias, ed., The Ultimate Challenge: The 3x+1 Problem, Amer. Math. Soc., 2010. See p. 307.
%H A181762 Vincenzo Librandi, <a href="/A181762/b181762.txt">Table of n, a(n) for n = 0..2000</a>
%H A181762 <a href="/index/3#3x1">Index entries for sequences related to 3x+1 (or Collatz) problem</a>
%H A181762 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,2,0,-1).
%F A181762 G.f.: -x*(-8 - x + 2*x^2) / ( (x-1)^2*(1+x)^2 ). - _R. J. Mathar_, Mar 10 2011
%p A181762 f:=n->if n mod 2 = 0 then n/2 else 3*x+5 fi;
%t A181762 Table[If[EvenQ[n],n/2,3n+5],{n,0,80}] (* _Harvey P. Dale_, Nov 25 2023 *)
%o A181762 (Magma) [(7*n+10-10*(-1)^n*(n/2+1))/4: n in [0..80]]; // _Vincenzo Librandi_, May 24 2011
%Y A181762 Cf. A006370.
%K A181762 nonn,easy
%O A181762 0,2
%A A181762 _N. J. A. Sloane_, Jan 31 2011