%I A006877 M0748
%S A006877 1,2,3,6,7,9,18,25,27,54,73,97,129,171,231,313,327,649,703,871,1161,2223,
%T A006877 2463,2919,3711,6171,10971,13255,17647,23529,26623,34239,35655,52527,
%U A006877 77031,106239,142587,156159,216367,230631,410011,511935,626331,837799
%N A006877 In the `3x+1' problem, these values for the starting value set new records 
               for number of steps to reach 1.
%C A006877 Both the 3x+1 steps and the halving steps are counted.
%D A006877 B. Hayes, Computer Recreations: On the ups and downs of hailstone numbers, 
               Scientific American, 250 (No. 1, 1984), pp. 10-16.
%D A006877 D. R. Hofstadter, Goedel, Escher, Bach: an Eternal Golden Braid, Random 
               House, 1980, p. 400.
%D A006877 G. T. Leavens and M. Vermeulen, 3x+1 search problems, Computers and Mathematics 
               with Applications, 24 (1992), 79-99.
%D A006877 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%H A006877 T. D. Noe, <a href="b006877.txt">Table of n, a(n) for n=1..130</a> (from 
               Eric Roosendaal's data)
%H A006877 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 A006877 R. Munafo, <a href="http://www.mrob.com/pub/math/seq-wondrous.html">Integer 
               Sequences Related to 3x+1 Collatz Iteration</a>
%H A006877 Eric Roosendaal, <a href="http://www.ericr.nl/wondrous/delrecs.html">
               3x+1 Delay Records</a>
%H A006877 <a href="Sindx_Go.html#GEB">Index entries for sequences from "Goedel, 
               Escher, Bach"</a>
%H A006877 <a href="Sindx_3.html#3x1">Index entries for sequences related to 3x+1 
               (or Collatz) problem</a>
%p A006877 A006877 := proc(n) local a,L; L := 0; a := n; while a <> 1 do if a mod 
               2 = 0 then a := a/2; else a := 3*a+1; fi; L := L+1; od: RETURN(L); 
               end;
%Y A006877 Cf. A006884, A006885, A006877, A006878, A033492.
%Y A006877 Sequence in context: A018700 A018295 A033495 this_sequence A085397 A073439 
               A107998
%Y A006877 Adjacent sequences: A006874 A006875 A006876 this_sequence A006878 A006879 
               A006880
%K A006877 nonn,nice
%O A006877 1,2
%A A006877 N. J. A. Sloane (njas(AT)research.att.com), mrob(AT)mrob.com (Robert 
               P Munafo)