%I #6 Feb 02 2020 16:02:29
%S 1,3,10,32,113,446,2038,11251,77689,685089,7798812
%N Number of prime implicants of the Y function of order n.
%C The Y function of order n is a self-dual monotone Boolean function of (n+1)(n+2)/2 points arranged in a triangular grid, with n+1 points on each side. Suppose we place black or white stones on that grid.
%C Then, as apparently first pointed out by John Milnor about 1950, either the white or black stones form a "Y" - that is, they touch all three sides of the board. (The corner points each touch two of the sides.)
%C The Y function tells us whether the white stones or the black stones have the Y.
%D D. E. Knuth, The Art of Computer Programming, Vol. 4A, Exercise 7.1.1-67.
%Y Cf. A134953.
%K nonn,more
%O 0,2
%A _Don Knuth_, Jan 26 2008