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A350754
Number of semi-strong digraphs on n unlabeled nodes.
3
1, 1, 2, 7, 91, 5144, 1052251, 706480081, 1581055927702, 12140606592270147, 328173093539912361767, 31831409057653120420337536, 11234306829106179168513020426663, 14576263867478482708779036941179024765, 70075728362112833245095630646535639894359350
OFFSET
0,3
COMMENTS
A digraph is semi-strong if all its weakly connected components are strongly connected.
LINKS
FORMULA
Euler transform of A035512.
CROSSREFS
The labeled version is A054948.
Row sums of A106238.
Cf. A035512.
Sequence in context: A376329 A096208 A123995 * A224439 A304722 A056161
KEYWORD
nonn
AUTHOR
Andrew Howroyd, Jan 14 2022
STATUS
approved