# A071535 (b-file synthesized from sequence entry) 1 1 2 15 3 176 4 1680 5 13824 6 102144 7 696320 8 4460544 9 27197440 10 159318016 11 902823936 12 4975493120 13 26776436736 14 141180272640 15 731218182144 16 3728300048384 17 18747532247040 18 93110596009984 19 457328117678080 20 2223830986653696 21 10715840324304896 22 51209754063667200