# A151477 (b-file synthesized from sequence entry) 0 1 1 1 2 3 3 10 4 35 5 138 6 566 7 2431 8 10780 9 49067 10 228355 11 1081997 12 5207905 13 25403962 14 125377203 15 625176432 16 3145870880 17 15959346050 18 81557403529 19 419547453308 20 2171222736256 21 11298086327362 22 59085844684247 23 310430932981503 24 1637929078223208 25 8676341846872322 26 46128302460092674 27 246081020287578117