

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, 181945055235
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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..15.
S. Hougardy, Home Page
S. Hougardy, Classes of perfect graphs, Discr. Math. 306 (2006), 25292571.
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,changed


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
a(15) added (using A048192) by Jakub Jablonski, Sep 15 2020


STATUS

approved



