# A138294 (b-file synthesized from sequence entry) 0 1 1 1 2 4 3 16 4 78 5 420 6 2454 7 15297 8 100660 9 694022 10 4986128 11 37171749 12 286619290 13 2279866324 14 18668221560 15 157080129914 16 1356186583276 17 11999018622158 18 108672944038356 19 1006528378511868 20 9525454067974148 21 92037443236217412