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

1,3

Links

Andrew Howroyd, Table of n, a(n) for n = 1..50

Eric Weisstein's World of Mathematics, Connected Digraph.

Formula

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

Crossrefs

Cf. A003085, A035512.

Sequence in context: A235338 A231553 A291077 * A085699 A046914 A364984

Adjacent sequences: A056985 A056986 A056987 * A056989 A056990 A056991

Keyword

nonn

Author

Eric W. Weisstein

Extensions

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

Status

approved