

A048781


Number of triangles in minimal triangle graphs.


1



1, 2, 5, 13, 35, 86, 250, 687, 2001, 5897, 17847, 54683, 170578, 537468, 1714312, 5516392, 17910741, 58588966, 193035920, 640132185, 2135841554, 7167550473, 24186506740
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OFFSET

3,2


COMMENTS

a(n) is the total number of triples in all the minimal triangle graphs on n points. That is, a(n) = Sum T for all A000080(n) triangle graphs G(T) on n points.


LINKS

Table of n, a(n) for n=3..25.
R. Bowen, The generation of minimal triangle graphs, Math. Comp. 21 (1967), 248250.


EXAMPLE

For n=3 points there is one minimal triangle graph containing one triple, so a(3) = 1.
For n=4 points there is one triangle graph containing two triples, so a(4) = 2.
For n=5 points there are two graphs, containing two and three triples, respectively, so a(5) = 2+3 = 5.
See also the illustration in A000080.


CROSSREFS

Cf. A000080.
Sequence in context: A112839 A331755 A137674 * A291242 A097919 A160438
Adjacent sequences: A048778 A048779 A048780 * A048782 A048783 A048784


KEYWORD

nonn,more,nice


AUTHOR

Arlin Anderson (starship1(AT)gmail.com)


EXTENSIONS

Edited by N. J. A. Sloane, Jan 22 2014
a(17)a(25) from Martin Fuller, Mar 23 2015


STATUS

approved



