# A053572 (b-file synthesized from sequence entry) 0 1 1 1 2 1 3 3 4 16 5 75 6 384 7 1805 8 8640 9 42336 10 207368 11 995808 12 5184000 13 24192672 14 121730700 15 594350400 16 2921811200