# A360462 (b-file synthesized from sequence entry) 0 1 1 1 2 2 3 6 4 24 5 120 6 720 7 5040 8 40320 9 362880 10 3548160 11 37054080 12 416551680 13 5050368000 14 65944535040 15 924630958080 16 13873661706240 17 221978587299840 18 3774394191052800 19 67494538767237120 20 1276009602375352320 21 25429720417085030400