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%I #6 Mar 31 2012 13:21:54
%S 1,8,6,17,20,15,10,18,13,21,8,16,24,112,19,107,27,14,22,35,110,30,17,
%T 105,25,25,12,113,33,33,20,108,28,28,15,103,116,15,23,36,23,111,10,31,
%U 31,93,18,106,119,26,26,88,39,101,114,70,13,34,21,34,96,47,109,47,122
%N Length of orbit of 2n+1 in the 3x+1 problem.
%H <a href="/index/3#3x1">Index entries for sequences related to 3x+1 (or Collatz) problem</a>
%F f(n)= n/2 if n is even, 3n+1 if n is odd; stop if n is 1.
%e E.g. orbit(3) = 3->10->5->16->8->4->2->1, so length of chain = 8
%o (ARIBAS): function a064685(maxarg: integer); var n: integer; begin for n := 1 to maxarg by 2 do write(length(orbit(n))," "); end; end; a064685(140). For definition of function orbit see A064684.
%K nonn,easy
%O 0,2
%A _Jon Perry_, Oct 10 2001
%E More terms from _Klaus Brockhaus_, Oct 13 2001
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