19022318084domain: NAppears in sequencesa(n) = binomial((n+1)^2, n) / (n+1)^2.at n=9A143669Number of symmetric 11-ary factorizations of the n-cycle (1,2...n).at n=18A192893a(n) = binomial(11*n+1,n)/(11*n+1).at n=9A230388