# A099216 (b-file synthesized from sequence entry) 0 1 1 2 2 4 3 10 4 28 5 80 6 228 7 648 8 1840 9 5224 10 14832 11 42112 12 119568 13 339488 14 963904 15 2736800 16 7770560 17 22062848 18 62642752 19 177860736 20 504997632 21 1433833088 22 4071063296 23 11558916096 24 32819077376 25 93182771712 26 264572609536