Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A000664
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A000664 Number of graphs with n edges.
(Formerly M1400 N0545)
+0
5
1, 2, 5, 11, 26, 68, 177, 497, 1476, 4613, 15216, 52944, 193367, 740226, 2960520, 12334829, 53394755, 239544624, 1111261697, 5320103252, 26237509076, 133087001869, 693339241737, 3705135967663 (list; graph; listen)
OFFSET

1,2

COMMENT

These are simple graphs, unlabeled, with no isolated nodes, but are not necessarily connected.

REFERENCES

W. Oberschelp, Kombinatorische Anzahlbestimmungen in Relationen, Math. Ann., 174 (1967), 53-78.

J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 146.

M. L. Stein and P. R. Stein, Enumeration of Linear Graphs and Connected Linear Graphs up to $p = 18$ Points. Report LA-3775, Los Alamos Scientific Laboratory of the University of California, Los Alamos, NM, Oct 1967.

LINKS

P. J. Cameron, Sequences realized by oligomorphic permutation groups, J. Integ. Seqs. Vol. 3 (2000), #00.1.5.

EXAMPLE

n=1: o-o (1)

n=2: o-o o-o (1)

n=3: o-o o-o o-o, o-o-o o-o, o-o-o-o, Y, triangle (5)

n=4: o-o o-o o-o o-o, o-o-o o-o o-o, o-o-o o-o-o, o-o o-o-o-o, o-o Y, o-o triangle,

o-o-o-o-o, >o-o-o, ><, square, triangle with tail (11)

CROSSREFS

Cf. A008406.

Sequence in context: A025245 A079223 A095892 this_sequence A067922 A095975 A006652

Adjacent sequences: A000661 A000662 A000663 this_sequence A000665 A000666 A000667

KEYWORD

nonn,nice

AUTHOR

njas

EXTENSIONS

More terms from Vladeta Jovovic (vladeta(AT)Eunet.yu), Jan 08 2000, Aug 14 2007

Edited by njas, Feb 26 2008

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified July 24 12:00 EDT 2008. Contains 142294 sequences.


AT&T Labs Research