A048192 Number of connected chordal graphs on n vertices.

1, 1, 2, 5, 15, 58, 272, 1614, 11911, 109539, 1247691, 17566431, 305310547, 6558690953, 174688164414, 5796153514484, 241003010628949, 12642592677074970, 842762851699294393, 71916937400532750123

Offset

1,3

Links

Table of n, a(n) for n=1..20.

Falk Hüffner, tinygraph, software for generating integer sequences based on graph properties, version 6e0a59d.

Tim Kemp, An algorithmic approach to a conjecture of Chvátal on toughness and hamiltonicity of graphs, M. Sc. Thesis, University of Twente (Netherlands, 2020).

B. D. McKay, Chordal graphs

Eric Weisstein's World of Mathematics, Chordal Graph

Eric Weisstein's World of Mathematics, Connected Graph

Formula

a(n) = A048193(n) - A287427(n). - Eric W. Weisstein, May 25 2017

Inverse Euler transform of A048193. - Andrew Howroyd, Nov 03 2017

Crossrefs

Cf. A048193 (not-necessarily connected chordal graphs).

Cf. A287427 (disconnected chordal graphs).

Cf. A048194.

Sequence in context: A334155 A373768 A348365 * A078792 A208808 A266682

Adjacent sequences: A048189 A048190 A048191 * A048193 A048194 A048195

Keyword

nonn,nice,more,changed

Author

Gordon Royle

Extensions

a(12) added by Gordon Royle, Aug 05 2008

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

a(15) added by Brendan McKay, Jan 07 2019

a(16)-a(20) from Matthew Sun, Jul 01 2026

Status

approved