# A262601 (b-file synthesized from sequence entry) 1 1 2 6 3 66 4 1176 5 31320 6 1174320 7 59184720 8 3866728320 9 318176449920 10 32215365100800 11 3937433507884800 12 571715345296972800 13 97295556944518732800 14 19183440644220345292800 15 4338408884154346729728000 16 1115590855925401950302208000 17 323670093665823262135185408000 18 105233239203100787701553799168000