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A034892
Number of balanced signed graphs on n unlabeled nodes.
2
1, 1, 3, 8, 39, 226, 2283, 36789, 1062679, 55717077, 5405078682, 972656526492, 325183692812200, 202373967993972497, 235081289816026793049, 511296223391186047847309, 2088912833728676472658628201, 16081914207958884651686215477871, 234010862353438997655954463710225233
OFFSET
0,3
REFERENCES
R. C. Read and R. J. Wilson, An Atlas of Graphs, Oxford, 1998.
LINKS
Wikipedia, Signed graph
FORMULA
Euler transform of A318590.
CROSSREFS
KEYWORD
nonn,nice
AUTHOR
Ronald C. Read
EXTENSIONS
Name clarified and offset corrected by Andrew Howroyd, Sep 25 2018
a(0)=1 prepended and terms a(13) and beyond from Andrew Howroyd, Sep 25 2018
STATUS
approved