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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A184974 Number of connected 7-regular simple graphs on 2n vertices with girth exactly 4. 7
0, 0, 0, 0, 0, 0, 0, 1, 1, 8, 741, 2887493 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,10

LINKS

Table of n, a(n) for n=0..11.

Jason Kimberley, Index of sequences counting connected k-regular simple graphs with girth exactly g

FORMULA

a(n) = A186714(n,5) - A186715(n,5).

EXAMPLE

a(0)=0 because even though the null graph (on zero vertices) is vacuously 7-regular and connected, since it is acyclic, it has infinite girth.

The a(7)=1 graph is the complete bipartite graph K_{7,7}.

CROSSREFS

Connected k-regular simple graphs with girth exactly 4: A006924 (k=3), A184944 (k=4), A184954 (k=5), A184964 (k=6), this sequence (k=7).

Connected 7-regular simple graphs with girth at least g: A014377 (g=3), A181153 (g=4).

Connected 7-regular simple graphs with girth exactly g: A184973 (g=3), this sequence (g=4).

Sequence in context: A058921 A240283 A181153 * A060183 A262353 A268148

Adjacent sequences:  A184971 A184972 A184973 * A184975 A184976 A184977

KEYWORD

nonn,more,hard

AUTHOR

Jason Kimberley, Feb 28 2011

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 September 18 05:32 EDT 2019. Contains 327165 sequences. (Running on oeis4.)