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%I #7 May 05 2014 14:42:22
%S 1,4,12,28,73,163,343,867,1915,4011,8203
%N a(1)=1. a(n)=smallest integer greater than 2*a(n-1) such that the Nim sequence of the first n terms is ternary, periodic and not equal to the Nim sequence of the first n-1 terms.
%C In the sequence definition, "Nim sequence of a set" means "Nim sequence of the subtraction game with that subtraction set."
%C This sequence is not known to be infinite.
%C If this sequence is infinite, then its Nim sequence is ternary and aperiodic.
%D E. R. Berlekamp, J. H. Conway and R. K. Guy, ``Winning Ways'', pp. 83-86
%H N. Fox, <a href="http://vimeo.com/93540244">Aperiodic Subtraction Games</a>, Talk given at the Rutgers Experimental Mathematics Seminar, May 01 2014.
%K nonn
%O 1,2
%A _Nathan Fox_, May 03 2014