# A174470 (b-file synthesized from sequence entry) 0 1 1 3 2 9 3 18 4 54 5 162 6 405 7 1215 8 3645 9 11907 10 35721 11 107163 12 279936 13 839808 14 2519424 15 6948099 16 20844297 17 62532891 18 199762767 19 599288301 20 1797864903 21 4931772480 22 14795317440 23 44385952320 24 125801650638 25 377404951914 26 1132214855742