# A121357 (b-file synthesized from sequence entry) 0 1 1 1 2 2 3 12 4 90 5 546 6 6156 7 81432 8 942012 9 15114780 10 294765336 11 5069224656 12 108842183352 13 2770895886552 14 64609245619920 15 1742542175582496 16 55074355772360976 17 1626315165597840912 18 53331321825434963232