# A099606 (b-file synthesized from sequence entry) 0 1 1 4 2 10 3 48 4 116 5 560 6 1352 7 6528 8 15760 9 76096 10 183712 11 887040 12 2141504 13 10340096 14 24963200 15 120532992 16 290992384 17 1405035520 18 3392055808 19 16378294272 20 39540700160 21 190919389184 22 460920178688 23 2225519493120 24 5372879343616