# A018083 (b-file synthesized from sequence entry) 0 1 1 2 2 4 3 7 4 13 5 25 6 47 7 90 8 169 9 321 10 610 11 1158 12 2197 13 4172 14 7922 15 15042 16 28561 17 54233 18 102979 19 195538 20 371293 21 705022 22 1338716 23 2541993 24 4826809 25 9165285 26 17403308 27 33045904 28 62748517 29 119148699 30 226242996