91366domain: NAppears in sequencesG.f. A(x,y) satisfies: A( x - x*y*A(x,y), y) = x + x*(1-y)*A(x,y), where the coefficients T(n,k) of x^n*y^k form a triangle read by rows n>=1, for k=0..n-1.at n=52A291820A diagonal of triangle A291820.at n=7A291822