# A056836 (b-file synthesized from sequence entry) 0 1 1 6 2 30 3 60 4 420 5 1260 6 13860 7 27720 8 360360 9 6126120 10 116396280 11 2677114440 12 5354228880 13 26771144400 14 80313433200 15 2329089562800 16 72201776446800 17 2671465728531600 18 109530094869795600 19 4709794079401210800