OFFSET
0,5
REFERENCES
F. Harary and E. M. Palmer, Graphical Enumeration, Academic Press, NY, 1973, p. 228.
FORMULA
MATHEMATICA
CROSSREFS
KEYWORD
nonn,nice
AUTHOR
EXTENSIONS
Using formula, a(0) and a(6) corrected and more terms added by Falk Hüffner, Nov 27 2015
STATUS
approved