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 A120618 Number of inequivalent (under "inversion of variables") monotone Boolean functions of n or fewer variables. 0
 1, 2, 4, 12, 90, 3831 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS We define the "inversion of variables", i, by (i.f)(x1,...,xn)=1+f(1+x1,...,1+xn). Note that {i,identity function} is a group. It turns out that if f is a monotone function, then i.f is also a monotone function. f is equivalent to g if f=g or f=i.g. LINKS EXAMPLE a(1)=2 because m(x)=0,n(x)=1,k(x)=x are the three monotone Boolean functions (of 1 or fewer variables) and m,n are equivalent. CROSSREFS Cf. A120608, A120587, A006602. Sequence in context: A053631 A319634 A217041 * A259048 A228809 A326945 Adjacent sequences:  A120615 A120616 A120617 * A120619 A120620 A120621 KEYWORD nonn,more AUTHOR Alan Veliz-Cuba (alanavc(AT)vt.edu), Jun 18 2006 STATUS approved

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Last modified November 30 04:28 EST 2021. Contains 349418 sequences. (Running on oeis4.)