A120608 Number of inequivalent (under the "inversion of variables") monotone Boolean nondegenerate functions of n variables.

1, 1, 1, 5, 59, 3470

Offset

0,4

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

Table of n, a(n) for n=0..5.

Example

a(2)=1 because f(x1,x2)=x1x2 is equivalent to g(x1,x2)=x1+x2+x1x2 and there are no more monotone Boolean nondegenerate functions of 2 variables.

Crossrefs

Sequence in context: A374345 A326573 A324240 * A143766 A132549 A091457

Adjacent sequences: A120605 A120606 A120607 * A120609 A120610 A120611

Keyword

nonn,more

Author

Alan Veliz-Cuba (alanavc(AT)vt.edu), Jun 16 2006

Status

approved