# A141254 (b-file synthesized from sequence entry) 0 1 1 1 2 2 3 6 4 24 5 110 6 510 7 2268 8 9632 9 39492 10 158190 11 624745 12 2447808 13 9552244 14 37214086 15 144932760 16 564676096 17 2201735552 18 8592780798 19 33568042425 20 131261440720 21 513747571680 22 2012524130518 23 7890178181831 24 30957296889264