# A218503 (b-file synthesized from sequence entry) 0 1 1 120 2 9765 3 251680 4 3043425 5 22661496 6 121226245 7 510902400 8 1799118945 9 5507702200 10 15072415941 11 37630041120 12 87029433985 13 188664603960 14 386925380325 15 756298318336 16 1417430759745 17 2559798038520 18 4472991338725 19 7589075296800 20 12538953723681