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A139627
Number of strongly connected directed multigraphs with loops allowed and with n arcs.
4
1, 1, 2, 4, 12, 37, 162, 738, 3928, 22436, 138716, 911529, 6339770, 46336941, 354453138, 2826472249, 23423053967, 201179882629, 1786791372857, 16377359709120, 154644691266520, 1502016160624186, 14985219655673207, 153377735526218010, 1608741204839374373
OFFSET
0,3
COMMENTS
The term a(0)=1 can be interpreted as either a singleton vertex or the graph with no vertices. - Andrew Howroyd, Jan 14 2022
LINKS
PROG
(PARI) \\ See PARI link in A350489 for program code.
A139627seq(20) \\ Andrew Howroyd, Jan 14 2022
CROSSREFS
Row sums of A139622.
Sequence in context: A193049 A114500 A148212 * A361720 A149844 A149845
KEYWORD
nonn
AUTHOR
Benoit Jubin, May 01 2008
EXTENSIONS
3 more terms from R. J. Mathar, Aug 04 2017
Terms a(7) and beyond from Andrew Howroyd, Jan 14 2022
STATUS
approved