# A229036 (b-file synthesized from sequence entry) 0 1 1 2 2 21 3 270 4 4212 5 77760 6 1662120 7 40415760 8 1102248000 9 33331979520 10 1107097891200 11 40069801094400 12 1569793384051200 13 66185883219456000 14 2988292627358438400 15 143855017177487616000 16 7355369573944584192000 17 398090614491857903616000 18 22737098558477268725760000