# A119831 (b-file synthesized from sequence entry) 0 1 1 6 2 1 3 720 4 120 5 1 6 362880 7 60480 8 504 9 1 10 479001600 11 79833600 12 665280 13 1320 14 1 15 1307674368000 16 217945728000 17 1816214400 18 3603600 19 2730 20 1 21 6402373705728000 22 1067062284288000 23 8892185702400 24 17643225600 25 13366080 26 4896 27 1