%I #12 Dec 22 2016 22:05:53
%S 1,1,1,1,1,1,5,2,1,1,1,9,13,13,13,13,13,2,13,13,17,13,13,5,13,13,13,
%T 22,13,5,29,1,13,13,13,29,13,13,13,7,13,1,17,13,29,1,13,1,33,49,13,20,
%U 31,11,13,11,3,19,13,19,61,13,61,13,61,27,49,10,13,40,13,34,37
%N a(n) = number at which the Ackermann function mod n stabilizes.
%C a(1969) is undefined, but otherwise a(n) is defined for all n >= 2 and < 4000000.
%H J. Froemke and J. W. Grossman, <a href="http://www.jstor.org/stable/2323780">A mod-n Ackermann function, or what's so special about 1969?</a>, Amer. Math. Monthly, 100 (1993), 180-183.
%H J. W. Grossman, <a href="http://www.oakland.edu/~grossman/">Home page</a>
%K nonn
%O 2,7
%A _Jerrold Grossman_, Apr 25 2004