login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A126732 Triangle read by rows: T(n,k) (n>=0, k=0..n) gives number of connected graphs on n nodes with edge chromatic number k. 3
1, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 2, 4, 0, 0, 0, 1, 8, 10, 2, 0, 0, 2, 26, 48, 36, 0, 0, 0, 1, 58, 279, 352, 159, 4, 0, 0, 2, 185, 1715, 4463, 3696, 1056, 0, 0, 0, 1, 500, 11464, 63363, 109760, 63605, 12378, 9, 0, 0, 2, 1677, 87114, 1066463, 3835747 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,13

LINKS

Table of n, a(n) for n=0..61.

Keith M. Briggs, Combinatorial Graph Theory

EXAMPLE

Triangle begins:

k..|.n=..1..2..3..4...5...6....7.....8.......9.......10

-------------------------------------------------------

0..|.....1..0..0..0...0...0....0.....0.......0........0

1..|.....0..1..0..0...0...0....0.....0.......0........0

2..|.....0..0..1..2...1...2....1.....2.......1........2

3..|.....0..0..1..4...8..26...58...185.....500.....1677

4..|.....0..0..0..0..10..48..279..1715...11464....87114

5..|.....0..0..0..0...2..36..352..4463...63363..1066463

6..|.....0..0..0..0...0...0..159..3696..109760..3835747

7..|.....0..0..0..0...0...0....4..1056...63605..4541399

CROSSREFS

Sequence in context: A028573 A138758 A107501 * A347679 A028586 A253179

Adjacent sequences:  A126729 A126730 A126731 * A126733 A126734 A126735

KEYWORD

nonn,tabl

AUTHOR

N. J. A. Sloane, Feb 16 2007

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 18 17:09 EDT 2021. Contains 348068 sequences. (Running on oeis4.)