

A116079


Number of connected trianglefree graphs on n nodes with chromatic number 3.


3



0, 0, 0, 0, 1, 2, 15, 85, 650, 5800, 65243, 931258, 17182237, 414512599, 13161989059
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OFFSET

1,6


LINKS



EXAMPLE

Table of number of connected trianglefree graphs on n nodes with chromatic number k begins:
(The first row is the same as the number of connected bipartite graphs on n nodes, A005142)
n=...1...2...3...4...5....6....7.....8.....9.....10......11.......12.........13
k.
2...0...1...1...3...5...17...44...182...730...4032...25598...212780....2241730 (A005142)
3...0...0...0...0...1....2...15....85...650...5800...65243...931258...17182237 (the present sequence)
4...0...0...0...0...0....0....0.....0.....0......0.......1.......23.......1085 (A126741)


CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS



STATUS

approved



