# A370926 (b-file synthesized from sequence entry) 0 1 1 1 2 2 3 6 4 28 5 220 6 2520 7 34510 8 519680 9 8527680 10 154831600 11 3151456000 12 71830281600 13 1809141934600 14 49559087177600 15 1459865188782000 16 45970426027926400 17 1543274016213529600 18 55120521154277779200 19 2088917638216953544000 20 83717918489664018560000