login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A018196 Possible numbers of complements of topologies on 5 points. 0
1, 4, 8, 9, 15, 32 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

J. I. Brown and S. Watson, The number of complements of a topology on n points is at least 2^n (except for some special cases), Discr. Math., 154 (1996), 27-39.

CROSSREFS

Cf. A000798.

Sequence in context: A131195 A020217 A141066 * A072103 A004756 A237882

Adjacent sequences:  A018193 A018194 A018195 * A018197 A018198 A018199

KEYWORD

nonn,more,fini

AUTHOR

N. J. A. Sloane

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 June 24 09:55 EDT 2019. Contains 324323 sequences. (Running on oeis4.)