34110720domain: NAppears in sequences(n-1)-st elementary symmetric function of {2, 3, 3, 4, 4, 5, 5,...,Floor[(n+4)/2]}.at n=10A203154Number of directed graphs of 2*n vertices each having an in-degree and out-degree of 1 such that the graph specifies a pairwise connected gift exchange with no reciprocal gifts.at n=6A322750