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Define two sequences by A_n = mex{A_i,B_i : 0 <= i < n} for n >= 0, B_0=0, B_1=1 and for n >= 2, B_n = 2B_{n-1}+(-1)^{A_n}. Sequence gives A_n.
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%I #15 Mar 10 2015 04:41:31

%S 0,1,2,4,5,6,8,9,10,11,12,14,15,16,17,18,19,20,21,22,23,24,25,26,28,

%T 29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,

%U 52,53,54,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76

%N Define two sequences by A_n = mex{A_i,B_i : 0 <= i < n} for n >= 0, B_0=0, B_1=1 and for n >= 2, B_n = 2B_{n-1}+(-1)^{A_n}. Sequence gives A_n.

%C The minimal excluded value of set of nonnegative numbers S is mex S = least nonnegative integer not in S.

%C The sequence B_n is given in A080241.

%H A. S. Fraenkel, <a href="http://www.wisdom.weizmann.ac.il/~fraenkel/">Home Page</a>

%H A. S. Fraenkel, <a href="http://www.emis.de/journals/INTEGERS/papers/eg6/eg6.Abstract.html">New games related to old and new sequences</a>, INTEGERS, Electronic J. of Combinatorial Number Theory, Vol. 4, Paper G6, 2004.

%Y Cf. A080241.

%K nonn

%O 0,3

%A _Aviezri S. Fraenkel_, Mar 12 2003

%E More terms from _Emeric Deutsch_, Apr 13 2005