A308239 Number of isomorphism classes of connected Eulerian oriented graphs with n vertices.

1, 1, 0, 1, 1, 4, 16, 175, 5274, 434017, 90658149, 48825116761, 68579602126387, 254236892409251687, 2512196983110257299898, 66738846701458593981832314, 4802164152196181961357340585741, 942009012794429918939576183310877477, 506665422212653541096106256584713063500057

Offset

0,6

Comments

Loops and 2-cycles are not permitted. Eulerian means that each vertex has equal in-degree and out-degree.

Links

Table of n, a(n) for n=0..18.

Formula

Inverse Euler transform of A308161.

Crossrefs

Cf. A308161.

Sequence in context: A005741 A033911 A130691 * A012916 A012921 A280468

Adjacent sequences: A308236 A308237 A308238 * A308240 A308241 A308242

Keyword

nonn,hard

Author

Alois P. Heinz, May 16 2019

Extensions

Terms a(12) and beyond from Andrew Howroyd, Apr 10 2020

Status

approved