# A318289 (b-file synthesized from sequence entry) 0 1 1 2 2 9 3 56 4 441 5 3952 6 40161 7 442248 8 5288933 9 67100072 10 904408398 11 12777826272 12 189324035423 13 2917525618256 14 46754429476800 15 774965979970096 16 13279872426589125 17 234395323126241080 18 4258775222885983350 19 79442662095373693728 20 1520453631213137081776