# A068181 (b-file synthesized from sequence entry) 0 1 1 18 2 1944 3 524880 4 264539520 5 214277011200 6 254561089305600 7 416971064282572800 8 900657498850357248000 9 2480410751833883860992000 10 8483004771271882804592640000 11 35272333838948488701496197120000