# A181784 (b-file synthesized from sequence entry) 0 1 1 1 2 4 3 22 4 140 5 969 6 7084 7 53820 8 420732 9 3782992 10 32389076 11 275617830 12 2350749914 13 20140518790 14 173429992350 15 1500850805160 16 14550277251918 17 133009333771170 18 1198324107797254