a(n) is the number of digraphs (not allowing loops) with vertices 1,2,...,n that have a unique Eulerian tour (up to cyclic shift).

A102693

a(n) is the number of digraphs (not allowing loops) with vertices 1,2,...,n that have a unique Eulerian tour (up to cyclic shift).

Terms

    a(0) =1a(1) =5a(2) =42a(3) =504a(4) =7920a(5) =154440a(6) =3603600a(7) =98017920a(8) =3047466240a(9) =106661318400

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