# A094370 (b-file synthesized from sequence entry) 0 1 1 2 2 3 3 8 4 45 5 288 6 140 7 17280 8 14175 9 89600 10 299376 11 17418240 12 5255250 13 402361344000 14 2501928000 15 98402304 16 488462349375 17 342372925440000 18 2534852320000 19 5377993912811520000 20 4842604238472 21 29967718809600000