A308128 Isomorphism classes of connected Eulerian digraphs with n vertices, allowing loops.

1, 2, 3, 14, 112, 2174, 124501, 22400498, 13010949171, 24926846389076, 160810397320789069, 3554744065897655673978, 273140190737719436311559660, 73831786956788218320014098284918, 70920392983384812245087697080226658475, 244186402549448674084991238687021028510453186

Offset

0,2

Links

Table of n, a(n) for n=0..15.

Formula

Inverse Euler transform of A308111.

Crossrefs

Cf. A058338, A229865, A308111.

Sequence in context: A041167 A294380 A343261 * A006279 A041521 A101003

Adjacent sequences: A308125 A308126 A308127 * A308129 A308130 A308131

Keyword

nonn,hard

Author

Alois P. Heinz, May 14 2019, following a suggestion from Brendan McKay

Extensions

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

Status

approved