A082166 a(n) = A006689(n)/n^2.

1, 3, 24, 328, 6427, 164765, 5228210, 197897582, 8704544263, 436312502297, 24550259053858, 1532241939881294, 105048412352334420, 7847739530288388636, 634523723233529394594, 55206024491463561241758

Offset

1,2

References

Valery A. Liskovets, The number of initially connected automata, Kibernetika, (Kiev), No3 (1969), 16-19; Engl. transl.: Cybernetics, v.4 (1969), 259-262.

Links

Table of n, a(n) for n=1..16.

Valery A. Liskovets, Exact enumeration of acyclic automata, Proc. 15th Conf. "Formal Power Series and Algebr. Combin. (FPSAC'03)", 2003.

Valery A. Liskovets, Exact enumeration of acyclic deterministic automata, Discrete Appl. Math., 154, No.3 (2006), 537-551.

Mathematica

b[n_] := b[n] = If[n == 1, 1, n^(2*n)/(n-1)! - Sum[n^(2*(n-i))*b[i]/(n-i)!, {i, 1, n-1}]];
a[n_] := b[n]/n^2;
Array[a, 16] (* Jean-François Alcover, Aug 28 2019 *)

Crossrefs

Cf. A006689.

Sequence in context: A232693 A319939 A375869 * A354259 A370055 A371007

Adjacent sequences: A082163 A082164 A082165 * A082167 A082168 A082169

Keyword

easy,nonn

Author

Valery A. Liskovets, Apr 09 2003

Status

approved