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%I #6 Aug 08 2015 23:59:33
%S 2,4,12,48,308,3028,49490,1350894,62154403
%N Number of inequivalent Krom functions on n variables (or 2SAT instances) under permutations of variables.
%D D. E. Knuth, The Art of Computer Programming, Vol. 4A, Section 7.1.1, p. 79.
%Y See A109457 for definitions and references.
%K nonn,hard,more
%O 0,1
%A _Don Knuth_, Aug 24 2005