# A077056 (b-file synthesized from sequence entry) 0 1 1 1 2 4 3 22 4 140 5 992 6 7584 7 61420 8 520320 9 4570292 10 41354416 11 383609434 12 3634231140 13 35059333218 14 343580813492 15 3413862553800 16 34336784362232 17 349131316634164 18 3584622273967324 19 37128374058146138 20 387630493693010928