# A099448 (b-file synthesized from sequence entry) 0 1 1 5 2 19 3 65 4 216 5 715 6 2369 7 7855 8 26051 9 86400 10 286549 11 950345 12 3151831 13 10453085 14 34667784 15 114976135 16 381319781 17 1264651795 18 4194233399 19 13910227200 20 46133441401 21 153002131805 22 507433471819 23 1682909416265 24 5581389996216