A091479 Number of graphs with n nodes. Nodes and edges labeled each from their own label set.

1, 1, 2, 16, 1957, 9864101, 3554627472076, 138879579704209680022, 828772446866981044847857913441, 1011182700521015817607065606491025592595137, 325166909258549255903203528672831330994640286650913570126

Offset: 0

Author

Christian G. Bower, Jan 13 2004

Keywords

• nonn

Links

• Andrew Howroyd, Table of n, a(n) for n = 0..30

Crossrefs

Row sums of A091478.

Cf. A006125.

Cf. A000217, A000522.

Programs

PARI

a(n)={binomial(n,2)!*sum(k=0, binomial(n,2), 1/k!)} \\ Andrew Howroyd, Feb 12 2020

Formula

a(n) = A000522(A000217(n-1)). - Gerald McGarvey, Nov 17 2007

Extensions

a(0)=1 prepended and terms a(10) and beyond from Andrew Howroyd, Feb 12 2020