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

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A048193 Number of chordal graphs (or triangulated graphs) on n vertices. 4
1, 2, 4, 10, 27, 94, 393, 2119, 14524, 126758, 1392387, 19109099, 326005775, 6905776799 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Graphs having no induced cycles of any length > 3, so every cycle in the graph has a chord, or is "triangulated".

All such graphs are perfect.

Euler transform of A048192. - Eric M. Schmidt, Mar 25 2015

LINKS

Table of n, a(n) for n=1..14.

S. Hougardy, Home Page

S. Hougardy, Classes of perfect graphs, Discr. Math. 306 (2006), 2529-2571.

Eric Weisstein's World of Mathematics, Chordal Graph

FORMULA

a(n) = A048192(n) + A287427(n).

CROSSREFS

Cf. A048192 (connected chordal graphs).

Cf. A287427 (disconnected chordal graphs).

Cf. A048194.

Sequence in context: A268522 A123428 A005975 * A123411 A278418 A321946

Adjacent sequences:  A048190 A048191 A048192 * A048194 A048195 A048196

KEYWORD

nonn,more

AUTHOR

Gordon F. Royle

EXTENSIONS

Edited by N. J. A. Sloane, Jul 04 2008

a(12) added (using A048192) by Eric M. Schmidt, Mar 25 2015

a(13) and a(14) added (using A048192) by Falk Hüffner, Jan 15 2016

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 January 20 06:07 EST 2019. Contains 319323 sequences. (Running on oeis4.)