# A183124 (b-file synthesized from sequence entry) 0 0 1 1 2 3 3 7 4 19 5 53 6 153 7 451 8 1339 9 4001 10 11981 11 35919 12 107727 13 323149 14 969409 15 2908187 16 8724515 17 26173497 18 78520437 19 235561255 20 706683703