3886091domain: NAppears in sequencesNumber of lower triangles of a 4X4 0..n array with each element differing from all of its diagonal, vertical, antidiagonal and horizontal neighbors by two or less.at n=23A195250G.f. satisfies A(x) = 1 + x*A(x) / (1 + x*A(x))^5.at n=13A365088