110724domain: NAppears in sequencesNumber of self-avoiding polygons of area n with 2 (self-avoiding polygon) holes on square lattice (not allowing rotations).at n=5A057407G.f. satisfies A(x) = ( 1 + x*A(x)^(5/2) / (1 - x*A(x)) )^2.at n=6A371581