OFFSET
1,4
REFERENCES
F. Harary and E. M. Palmer, Graphical Enumeration, Academic Press, 1973, section 1.2.
LINKS
Marko Riedel et al., Proof of recurrence relation.
Marko Riedel, Maple implementation of memoized recurrence.
FORMULA
a(n) = A143543(n+1, 3) for n >= 1 and a(0) = 0.
E.g.f.: log(Sum_{q>=0} 2^binomial(q, 2)*z^q/q!)^3/3!.
CROSSREFS
KEYWORD
nonn
AUTHOR
Marko Riedel, Feb 05 2019
STATUS
approved