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!)
A067309 Number of symmetric unlabeled digraphs (unlabeled digraphs with nontrivial automorphism group). 0
0, 0, 2, 9, 82, 1607, 95647 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..6.

FORMULA

a(n) = A000273(n) - A051504(4)

EXAMPLE

For n=4 nodes from the 218 (=A000273(4)) unlabeled nonisomorphic digraphs 136(=A051504(4)) are asymmetric, so 218-136=82 are somehow symmetric.

CROSSREFS

Cf. A000273, A051504.

Sequence in context: A110567 A123570 A006040 * A087798 A113146 A323769

Adjacent sequences:  A067306 A067307 A067308 * A067310 A067311 A067312

KEYWORD

nonn,more

AUTHOR

Labos Elemer, Jan 11 2002

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 January 24 01:05 EST 2020. Contains 331178 sequences. (Running on oeis4.)