464333035881domain: NAppears in sequencesa(n) = binomial(n*(n+1),n)/(n^2+1).at n=10A135862Number of symmetric 11-ary factorizations of the n-cycle (1,2...n).at n=20A192893a(n) = binomial(11*n+1,n)/(11*n+1).at n=10A230388