# A131978 (b-file synthesized from sequence entry) 1 1 2 1 3 1 4 4 5 4 6 24 7 24 8 192 9 1728 10 17280 11 17280 12 207360 13 207360 14 414720 15 6220800 16 99532800 17 696729600 18 12541132800 19 12541132800 20 250822656000 21 5267275776000 22 10534551552000 23 10534551552000 24 252829237248000 25 1264146186240000 26 12641461862400000 27 3754514173132800000