The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A128241 Number of n-node (unlabeled) connected graphs with girth 4. 4
0, 1, 2, 11, 41, 220, 1243, 9368, 89049, 1135894, 19381407, 445505570, 13741579905, 566739127723, 31124921885829 (list; graph; refs; listen; history; text; internal format)
OFFSET
3,3
LINKS
Table of n, a(n) for n=3..17.
FORMULA
a(n) = A024607(n) - A126757(n). - Martin Fuller, May 01 2015
CROSSREFS
Cf. A024607, A126757.
Cf. A128041, A128042, A128236-A128243.
Sequence in context: A203574 A070778 A260267 * A258937 A347110 A225907
Adjacent sequences: A128238 A128239 A128240 * A128242 A128243 A128244
KEYWORD
nonn,more
AUTHOR
Keith Briggs, May 05 2007
EXTENSIONS
Corrected and extended by Martin Fuller, May 01 2015
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 14 05:21 EDT 2024. Contains 372528 sequences. (Running on oeis4.)