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%I #5 May 10 2013 12:45:46
%S 1,2,27,572,16787,631362,28980861,1570956872,98212870233,
%T 6956704585554,550626446263423,48163137319172436,4613554511554200251,
%U 480324019903607680066,54004504167811544647161,6521368218660772789452944
%N Number of labeled directed multigraphs (without loops) with n arcs and no vertex of degree 0.
%H Nathaniel Johnston, <a href="/A121137/b121137.txt">Table of n, a(n) for n = 0..50</a>
%p seq(sum(binomial(m*(m-1)+n-1,n)/2^(m+1),m=0..infinity),n=0..10);
%Y Cf. A052170 (unlabeled analog), A104209, A052171.
%K easy,nonn
%O 0,2
%A _Vladeta Jovovic_, Sep 06 2006
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