OFFSET
0,2
COMMENTS
A 2-colored labeled graph is a simple labeled graph in which each vertex is painted black or white and black vertices are only connected to white vertices and vice versa. [corrected by Geoffrey Critzer, Mar 27 2023]
FORMULA
E.g.f.: Sum_{n>=0} exp(1 + y)^n*x^n/n!
EXAMPLE
Triangle begins:
1;
2;
4, 2;
8, 12, 6;
16, 48, 60, 32, 6;
32, 160, 360, 440, 310, 120, 20;
64, 480, 1680, 3480, 4680, 4212, 2520, 960, 210, 20;
...
MATHEMATICA
nn=6; f[x_, y_]:=Sum[Exp[x (1+y)^n]x^n/n!, {n, 0, nn}]; Map[Select[#, #>0&]&, Range[0, nn]!CoefficientList[Series[f[x, y], {x, 0, nn}], {x, y}]]//Grid
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
Geoffrey Critzer, Sep 07 2013
STATUS
approved