digraph G {
        d2ttikzedgelabels = true;
        d2tstyleonly = true;
        d2tdocpreamble = "\usetikzlibrary{automata}";
        d2tfigpreamble = "\tikzstyle{every state}=\
        [draw=blue!50,shape=circle, very thick,fill=blue!20]";
        edge [lblstyle="fill=blue!20", style="arrows=->", topath="bend left"];
        node [style="state"];

        a_1 [style="state, initial"]
        a_1 -> a_2 [texlbl="1"]
        a_1 -> a_3 [texlbl="2"];
        a_1 -> a_4 [texlbl="3"];

        a_2 -> a_1 [texlbl="4"];
        a_2 -> a_3 [texlbl="5"];

        a_3 -> a_1 [texlbl="7"];
        a_3 -> a_2 [texlbl="8"];

        a_4 -> a_1 [texlbl="10",shape="circle"];
        a_4 [style="state, accepting"];
}