A054934 Number of oriented graphs on n nodes up to reversing the arcs.

1, 2, 6, 30, 342, 11164, 1077370, 287640989, 207974848520, 408004023529326, 2187203136795598146, 32269918474347692838600, 1318898367787065334889143452, 150182948079490899321955309512894, 47886343174490577986560743878301096450, 42944209124580582731273744197913175367709988

Offset: 1

Author

N. J. A. Sloane, May 24 2000

Keywords

• nonn
• easy

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..50
• V. A. Liskovets, Some easily derivable sequences, J. Integer Sequences, 3 (2000), #00.2.2.

Crossrefs

Cf. A001174, A005639.

Programs

Mathematica

A001174 = Cases[Import["https://oeis.org/A001174/b001174.txt", "Table"], {, }][[All, 2]];
A005639 = Cases[Import["https://oeis.org/A005639/b005639.txt", "Table"], {, }][[All, 2]];
a[n_] := (A001174[[n]] + A005639[[n]])/2;
Array[a, 50] (* Jean-François Alcover, Sep 01 2019 *)

Formula

Average of A001174 and A005639.

Extensions

More terms from Philip Sung (phil(AT)main.nu), May 07 2001

Terms a(15) and beyond from Andrew Howroyd, Sep 16 2018