A020563 Number of cyclic multigraphs on n labeled edges (with loops).

1, 2, 9, 68, 750, 11178, 213895, 5068102, 144746329, 4880572564, 191104219619, 8573780527428, 435844228476008, 24868815362420244, 1579939008182007447, 110981916769308996238, 8567134375799509782211

Offset: 0

Author

Gilbert Labelle (gilbert(AT)lacim.uqam.ca), Simon Plouffe

Keywords

• nonn

Links

• G. Labelle, Counting enriched multigraphs according to the number of their edges (or arcs), Discrete Math., 217 (2000), 237-248.
• G. Paquin, Dénombrement de multigraphes enrichis, Mémoire, Math. Dept., Univ. Québec à Montréal, 2004. [Cached copy, with permission]

Crossrefs

Cf. A014501.

Formula

a(n) = Sum_{k=0..n} (-1)^(n-k)*Stirling1(n, k)*A014501(k). - Sean A. Irvine, Apr 25 2019