login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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

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

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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

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