25165822domain: NAppears in sequencesa(n) = 3*2^n - 2.at n=23A033484Duplicate of A033484.at n=23A099018Number of bisymmetric, quasitrivial, and order-preserving binary operations on the n-element set {1,...,n}.at n=24A296953a(n) = n! * [x^n] (2*x - 4*exp(x) + 3*exp(2*x) + 3) / 2.at n=24A369491