A185193 Number of unlabeled digraphs on n vertices such that every vertex has outdegree 3.

0, 0, 0, 1, 13, 1499, 257290, 56150820, 14971125930, 4829990898461, 1864386642498918, 851204815909786099, 454661054439318678263, 281270600132956104641972, 199701092658236514672384967, 161392692052798327047616107614, 147373164027242947672475065773269

Offset: 1

Author

Nathaniel Johnston, Feb 08 2012

Keywords

• nonn

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..50
• L. Travis, [math/9811127] Graphical Enumeration: A Species-Theoretic Approach

Crossrefs

Column k=3 of A329228.

Cf. A001373, A129524, A185194, A185303.

Extensions

Terms a(10) and beyond from Andrew Howroyd, Nov 08 2019