%I
%S 1,1,2,4,4,8,8,8,8,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,
%T 16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,
%U 16,16,16,16,16,16,16,16
%N Periodicity of entries in the first row of a Laver Table of size 2^n.
%C All sequence elements are powers of 2. The first n for which a(n)=32 is at least A(9,A(8,A(8,255))), where A denotes the Ackermann function (R. Dougherty). If a rankintorank exists, then the sequence is diverging (R. Laver).
%H Richard Laver, <a href="http://arxiv.org/pdf/math/9204204v1">On the Algebra of Elementary Embeddings of a Rank into Itself</a>, Advances in Mathematics 110, p. 334, 1995
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Laver_table">Laver table</a>
%e a(4)=4 because the entries in the first row of the Laver table of size 4^2=16 are 2,12,14,16,2,12,14,16,2,12,14,16,2,12,14,16 (and thus repeat with a periodicity of 4).
%K nonn
%O 0,3
%A _Christian Schroeder_, Oct 08 2004
%E More terms from _Adam P. Goucher_, Dec 18 2013
