# A375633 (b-file synthesized from sequence entry) 0 1 1 1 2 4 3 15 4 84 5 555 6 4440 7 41265 8 438480 9 5240025 10 69582240 11 1016350335 12 16194911040 13 279560396115 14 5197054262400 15 103514720133825 16 2199255573715200 17 49645309340451825 18 1186599954328588800 19 29937224154635772975 20 795051251297099596800