# A006573 (b-file synthesized from sequence entry) 0 1 1 1 2 1 3 2 4 8 5 16 6 384 7 768 8 3072 9 6144 10 1474560 11 589824 12 11796480 13 7864320 14 11890851840 15 23781703680 16 95126814720 17 27179089920 18 91321742131200 19 7305739370496 20 730573937049600 21 1461147874099200 22 385743038762188800 23 771486077524377600