# A111538 (b-file synthesized from sequence entry) 0 1 1 3 2 14 3 84 4 600 5 4908 6 44952 7 454344 8 5016768 9 60062352 10 775089312 11 10728930912 12 158638465536 13 2496437377728 14 41674737264000 15 735831528563328 16 13704461848753152 17 268562085051533568 18 5525005742876244480