# A149468 (b-file synthesized from sequence entry) 0 1 1 1 2 4 3 13 4 54 5 212 6 916 7 3984 8 17758 9 80159 10 367710 11 1700619 12 7930388 13 37241889 14 175959334 15 835236876 16 3981398689 17 19051204957 18 91454768190 19 440232013360 20 2124509433674 21 10275936003671 22 49800985817062 23 241783261316646 24 1175778895993067 25 5726143038966814 26 27923583090576487 27 136335309089326590