# A052878 (b-file synthesized from sequence entry) 0 0 1 2 2 6 3 34 4 276 5 2928 6 38520 7 606240 8 11118240 9 232928640 10 5488922880 11 143707737600 12 4138613740800 13 130021152307200 14 4425207423436800 15 162194949242726400 16 6369480464675328000 17 266808295408951296000 18 11874724735152254976000 19 559591803705456377856000