# A119940 (b-file synthesized from sequence entry) 2 3 3 32 4 135 5 3456 6 3500 7 172800 8 694575 9 6272000 10 6286896 11 762048000 12 763062300 13 129090931200 14 129196782000 15 129282177024 16 517408266375 17 149597947699200 18 149654059755200 19 54042258606336000 20 54056895051375216