# A007167 (b-file synthesized from sequence entry) 0 1 1 1 2 4 3 15 4 62 5 271 6 1247 7 5938 8 29113 9 145815 10 743384 11 3844314 12 20118681 13 106348391 14 567002169 15 3045455865 16 16463622763 17 89509216860 18 489103356753 19 2684663659765 20 14795752770278 21 81841297482116 22 454202999050433 23 2528381760697852