# A216466 (b-file synthesized from sequence entry) 0 0 1 0 2 0 3 3 4 8 5 15 6 48 7 105 8 384 9 945 10 3840 11 10395 12 46080 13 135135 14 645120 15 2027025 16 10321920 17 34459425 18 185794560 19 654729075 20 3715891200 21 13749310575 22 81749606400 23 316234143225 24 1961990553600 25 7905853580625 26 51011754393600 27 213458046676875 28 1428329123020800