The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A213434 a(n) is the number of labeled triangle-free simple graphs on n vertices. 2
 1, 2, 7, 41, 388, 5789, 133501, 4682270, 246348115, 19213627145, 2198376297964, 365587270414697, 87628189849380625, 30044424979717359410, 14633141237888767056799, 10059886640779846047089825 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Former name: Number of n X n symmetric binary matrices with zero diagonal and no three-node loops x(i,j)*x(j,k)*x(k,i) = 1, i < j < k. From Brendan McKay, Jun 11 2021: (Start) EXP transform of A345218. Labeled version of A006785. (End) LINKS Table of n, a(n) for n=1..16. Tobias Boege and Thomas Kahle, Construction Methods for Gaussoids, arXiv:1902.11260 [math.CO], 2019. Falk Hüffner, tinygraph, software for generating integer sequences based on graph properties, version 8c665c7 EXAMPLE Some solutions for n=4: 0 1 0 0 0 1 1 0 0 1 0 0 0 0 1 1 0 1 0 0 1 0 1 0 1 0 0 1 1 0 0 0 0 0 1 0 1 0 0 1 0 1 0 1 1 0 0 1 0 0 0 1 1 1 0 0 0 0 0 0 0 0 1 0 0 1 1 0 0 0 1 0 1 0 0 0 0 1 0 0 CROSSREFS Cf. A006785, A345218. Sequence in context: A047864 A173916 A163921 * A331920 A008934 A084871 Adjacent sequences: A213431 A213432 A213433 * A213435 A213436 A213437 KEYWORD nonn,more AUTHOR R. H. Hardin, Jun 11 2012 EXTENSIONS a(11)-a(13) added using tinygraph by Falk Hüffner, Jun 19 2018 a(14)-a(15) added using tinygraph by Falk Hüffner, Oct 28 2019 a(16) added by Brendan McKay, Sep 15 2020 Name changed to the one suggested by Falk Hüffner and Brendan McKay, Jun 11 2021 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.

Last modified May 29 15:14 EDT 2023. Contains 363042 sequences. (Running on oeis4.)