# A174727 (b-file synthesized from sequence entry) 0 2 1 6 2 8 3 180 4 288 5 10080 6 17280 7 453600 8 806400 9 47900160 10 87091200 11 217945728000 12 402361344000 13 2241727488000 14 4184557977600 15 2000741783040000 16 3766102179840000 17 2838385676206080000 18 5377993912811520000 19 1686001091666411520000 20 3211430650793164800000 21 423033001181754163200000