%I A072105
%S A072105 3,5,8,7,10,10,11,15,22,20,20,21,30,28,28,29,42,38,37,55,90,66,55,87,
%T A072105 150,100,76,65,102,80,70,66,65,102,80,70,66,65,97,160,115,194,134,105,
%U A072105 171,302,192,138,112,100,95,144,119,190,144,122,112,108,107,160,135
%N A072105 Let c(1)=x, c(n+1) = c(n)/2 + n if c(n) is even, c(n+1)= 2c(n) - n otherwise; 
               then a(n)=c(n) for c(1)=3.
%C A072105 It seems that for any n, 2n <= a(n) <16n. If x=0,1,2,4 or 6 we have c(k+1)-c(k)=2 
               for k large enough and then lim k -> infinity c(k)/k=2. For x=3,5 
               and for any x >6 there is a conjectured constant 4 < C < 5 such that 
               lim N -> infinity (1/N)*sum(k=1,N,c(k)/k) = C. Hence lim N -> infinity 
               (1/N)*sum(k=1,N,a(k)/k) should be C=4.6...
%e A072105 a(1)=3 is odd hence a(2)=2*a(1)-1= 2*3-1 =5
%Y A072105 Sequence in context: A021740 A110641 A121729 this_sequence A088509 A120098 
               A081859
%Y A072105 Adjacent sequences: A072102 A072103 A072104 this_sequence A072106 A072107 
               A072108
%K A072105 easy,nonn
%O A072105 1,1
%A A072105 Benoit Cloitre (benoit7848c(AT)orange.fr), Jul 30 2002