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%I #13 Jan 13 2021 01:21:41
%S 1,1,8,108,2200,61708,2249268,102377404,5651999688,370171228504,
%T 28262385542832,2480108374814480,247231765611893504,
%U 27722619251007202720,3467475213036160205984,480277499859342401636704,73202023124111697153718080,12209186681659842887207280448
%N Consider the family of directed multigraphs enriched by the species of involutions. Sequence gives number of those multigraphs with n labeled arcs.
%D G. Paquin, Dénombrement de multigraphes enrichis, Mémoire, Math. Dept., Univ. Québec à Montréal, 2004.
%H Andrew Howroyd, <a href="/A099699/b099699.txt">Table of n, a(n) for n = 0..100</a>
%H G. Paquin, <a href="/A038205/a038205.pdf">Dénombrement de multigraphes enrichis</a>, Mémoire, Math. Dept., Univ. Québec à Montréal, 2004. [Cached copy, with permission]
%F E.g.f.: B(R(x)) where B(x) is the e.g.f. of A014505 and 1 + R(x) is the e.g.f. of A000085. - _Andrew Howroyd_, Jan 12 2021
%o (PARI) \\ R(n) is A000085 as e.g.f.; EnrichedGdSeq defined in A098623.
%o R(n)={exp(x+x^2/2 + O(x*x^n))}
%o EnrichedGdSeq(R(20)) \\ _Andrew Howroyd_, Jan 12 2021
%Y Cf. A000085, A014505, A098623, A099696, A099697, A099698.
%K nonn
%O 0,3
%A _N. J. A. Sloane_, Oct 26 2004
%E Terms a(11) and beyond from _Andrew Howroyd_, Jan 12 2021