OFFSET
3,1
FORMULA
O.g.f.: (1-x)*(1-x^2)* G(x) where G(x) is o.g.f. for A000088
MATHEMATICA
nn = 20; g = Sum[NumberOfGraphs[n] x^n, {n, 0, nn}]; Drop[CoefficientList[Series[ g (1 - x) (1 - x^2), {x, 0, nn}], x], 3]
CROSSREFS
KEYWORD
nonn
AUTHOR
Geoffrey Critzer, Apr 15 2012
STATUS
approved