A056988 Number of weakly connected digraphs on n unlabeled nodes that are not strongly connected.

0, 1, 8, 116, 4316, 483835, 175048780, 212125583518, 887136857205696, 13086449050056880074, 691487226135525983266460, 132437909864451274070001431956, 92821692762628588679459049647697100, 239928160288841627346208269001938306502290

Offset: 1

Author

Eric W. Weisstein

Keywords

• nonn

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..50
• Eric Weisstein's World of Mathematics, Connected Digraph.

Crossrefs

Cf. A003085, A035512.

Formula

a(n) = A003085(n) - A035512(n).

Extensions

a(12)-a(14) added by Andrew Howroyd, Dec 27 2021