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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A033886 Number of connected 4-regular simple graphs on n vertices with girth at least 4. 20
 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 2, 2, 12, 31, 220, 1606, 16828, 193900, 2452818, 32670330, 456028474, 6636066099, 100135577747, 1582718912968 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,11 COMMENTS The null graph on 0 vertices is vacuously connected and 4-regular; since it is acyclic, it has infinite girth. - Jason Kimberley, Jan 29 2011 REFERENCES M. Meringer, Fast Generation of Regular Graphs and Construction of Cages. Journal of Graph Theory, 30 (1999), pp. 137-146. LINKS Jason Kimberley, Connected regular graphs with girth at least 4 M. Meringer, Tables of Regular Graphs CROSSREFS Contribution from Jason Kimberley, Mar 19 2010 and Jan 28 2011: (Start) 4-regular simple graphs with girth at least 4: this sequence (connected), A185244 (disconnected), A185344 (not necessarily connected). Connected k-regular simple graphs with girth at least 4: A186724 (any k), A186714 (triangle); specified degree k: A185114 (k=2), A014371 (k=3), this sequence (k=4), A058275 (k=5), A058276 (k=6), A181153 (k=7), A181154 (k=8), A181170 (k=9). Connected 4-regular simple graphs with girth at least g: A006820 (g=3), this sequence (g=4), A058343 (g=5), A058348 (g=6). Connected 4-regular simple graphs with girth exactly g: A184943 (g=3), A184944 (g=4), A184945 (g=5). (End) Sequence in context: A093044 A151366 A184944 * A185144 A185344 A237275 Adjacent sequences:  A033883 A033884 A033885 * A033887 A033888 A033889 KEYWORD nonn,nice,more,hard AUTHOR N. J. A. Sloane, Dec 17 2000 EXTENSIONS By running M. Meringer's GENREG at U. Newcastle for 6.25, 107 and 1548 processor days, a(21), a(22), and a(23) were completed by Jason Kimberley on Dec 06 2009, Mar 19 2010, and Nov 02 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.

Last modified May 26 08:39 EDT 2020. Contains 334620 sequences. (Running on oeis4.)