# A217041 (b-file synthesized from sequence entry) 0 1 1 2 2 4 3 12 4 88 5 624 6 4112 7 32912 8 293280 9 2576896 10 23669376 11 233756544 12 2372829696 13 24679378432 14 268444154624 15 3026232635648 16 35050705650176 17 420323656792064 18 5218917552457728 19 66738035973859328 20 880566524142424064 21 11998061103578816512 22 168314109964357738496