# A147840 (b-file synthesized from sequence entry) 0 1 1 8 2 72 3 656 4 5984 5 54592 6 498048 7 4543744 8 41453056 9 378180608 10 3450181632 11 31476371456 12 287162261504 13 2619811643392 14 23900818341888 15 218049690271744 16 1989290355982336 17 18148506037649408 18 165570737528635392