%I A003028 M3157
%S A003028 1,3,51,3614,991930,1051469032,4366988803688,71895397383029040,
%T A003028 4719082081411731363408,1237678715644664931691596416,
%U A003028 1297992266840866792981316221144960
%N A003028 Number of n-node digraphs with a source.
%D A003028 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A003028 R. W. Robinson, Counting labeled acyclic digraphs, pp. 239-273 of F. 
               Harary, editor, New Directions in the Theory of Graphs. Academic 
               Press, NY, 1973.
%D A003028 V. Jovovic and G. Kilibarda, Enumeration of labeled initially-finally 
               connected digraphs, Scientific review, Serbian Scientific Society, 
               19-20 (1996) 237-247.
%D A003028 V. Jovovic and G. Kilibarda, Enumeration of labeled quasi-initially connected 
               digraphs, Discrete Math., 224 (2000), 151-163.
%Y A003028 Sequence in context: A075869 A126685 A105639 this_sequence A069343 A084882 
               A091502
%Y A003028 Adjacent sequences: A003025 A003026 A003027 this_sequence A003029 A003030 
               A003031
%K A003028 nonn,easy,nice
%O A003028 1,2
%A A003028 N. J. A. Sloane (njas(AT)research.att.com).
%E A003028 Corrected and extended by Vladeta Jovovic, Goran Kilibarda (vladeta(AT)eunet.rs)