# A103973 (b-file synthesized from sequence entry) 0 1 1 2 2 4 3 4 4 24 5 16 6 160 7 80 8 1120 9 448 10 8064 11 2688 12 59136 13 16896 14 439296 15 109824 16 3294720 17 732160 18 24893440 19 4978688 20 189190144 21 34398208 22 1444724736 23 240787456 24 11076222976 25 1704034304 26 85201715200 27 12171673600 28 657270374400