A099704 Consider the family of multigraphs enriched by the species of directed graphs. Sequence gives number of those multigraphs with n labeled edges.

1, 2, 24, 776, 79840, 35397440, 69619053504, 564929183555840, 18464894708236907776, 2418517115222622481308160, 1267747370909677813160722947072, 2658511777246500251150215101758228480, 22300872810108738542496498718468714032205824

Offset

0,2

References

G. Paquin, Dénombrement de multigraphes enrichis, Mémoire, Math. Dept., Univ. Québec à Montréal, 2004.

Links

Andrew Howroyd, Table of n, a(n) for n = 0..50

G. Paquin, Dénombrement de multigraphes enrichis, Mémoire, Math. Dept., Univ. Québec à Montréal, 2004. [Cached copy, with permission]

Formula

E.g.f.: B(R(x)) where B(x) is the e.g.f. of A014500 and 1 + R(x) is the e.g.f. of A002416. - Andrew Howroyd, Jan 12 2021

Prog

(PARI) \\ R(n) is A002416 as e.g.f.; EnrichedGnSeq defined in A098620.
R(n)={sum(k=0, n, 2^(k^2)*x^k/k!) + O(x*x^n)}
EnrichedGnSeq(R(15)) \\ Andrew Howroyd, Jan 12 2021

Crossrefs

Cf. A002416, A014500, A098620, A099705, A099706, A099707.

Sequence in context: A274634 A292694 A012128 * A265879 A339946 A172492

Adjacent sequences: A099701 A099702 A099703 * A099705 A099706 A099707

Keyword

nonn

Author

N. J. A. Sloane, Oct 26 2004

Extensions

Terms a(10) and beyond from Andrew Howroyd, Jan 12 2021

Status

approved