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Number of prime implicants of the Y function of order n.
1

%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