937974536domain: NAppears in sequencesE.g.f.: A(x) + B(x) + C(x) where A'(x) = B(x)*C(x), B'(x) = A(x)*C(x), and C'(x) = A(x)*B(x), where A(x), B(x), and C(x) are the e.g.f.s of A292121, A292122, and A292123, respectively.at n=9A292120