# A009156 (b-file synthesized from sequence entry) 0 1 1 0 2 1 3 -3 4 20 5 -140 6 1216 7 -12096 8 137080 9 -1737504 10 24368656 11 -374527120 12 6259083896 13 -112992788688 14 2191121957480 15 -45420491782680 16 1002232901602496 17 -23453004823018496 18 580102806342112960