# A375639 (b-file synthesized from sequence entry) 0 1 1 0 2 0 3 12 4 24 5 80 6 2520 7 17136 8 124320 9 2462400 10 30965760 11 372113280 12 7014807360 13 122840789760 14 2078973921024 15 43236813312000 16 932206147891200 17 20090534745415680 18 480054835899371520 19 12126262777282805760 20 313198020852233932800