login
A129524
Number of unlabeled digraphs on n vertices such that every vertex has outdegree 2.
6
0, 0, 1, 6, 79, 1499, 35317, 967255, 29949217, 1033242585, 39323062014, 1637375262965, 74075329383599, 3619112881630497, 189953824713590782, 10661151595417930874, 637230479685691806302, 40415532825383300892418, 2711124591869919503655096
OFFSET
1,4
CROSSREFS
Column k=2 of A329228.
Sequence in context: A156929 A123796 A184553 * A131237 A024082 A132547
KEYWORD
nonn
AUTHOR
Vladeta Jovovic, May 29 2007
EXTENSIONS
Terms a(10) and beyond from Andrew Howroyd, Nov 08 2019
STATUS
approved