OFFSET
1,3
COMMENTS
From Sean A. Irvine, Feb 05 2015: (Start)
Converse means reversing the direction of every arc.
Complement means every arc not in the original.
The digraph here have no loops and vertices are unlabelled.
Table 1 on p. 200 of Palmer reference erroneously has a(4) = 5. (End)
REFERENCES
E. M. Palmer, Graphical enumeration problems, pp. 187-206 of F. Harary, editor, New Directions in the Theory of Graphs. Academic Press, NY, 1973.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
Sean A. Irvine, Table of n, a(n) for n = 1..36
Sean A. Irvine, Illustration of initial terms
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
a(4) corrected and more terms from Sean A. Irvine, Feb 05 2015
STATUS
approved