# A149618 (b-file synthesized from sequence entry) 0 1 1 1 2 5 3 15 4 65 5 231 6 1077 7 4077 8 19521 9 77847 10 375523 11 1542669 12 7503275 13 31482945 14 153831367 15 656080547 16 3217363353 17 13890626113 18 68303798347 19 297856509483 20 1467615828795 21 6451956824907 22 31844333302963 23 140944569490221 24 696579282949195 25 3100862322964479 26 15342444196387139 27 68634610543557457