# A181471 (b-file synthesized from sequence entry) 1 1 2 4 3 8 4 16 5 20 6 34 7 47 8 72 9 95 10 126 11 168 12 208 13 262 14 343 15 433 16 507 17 634 18 799 19 976 20 1146 21 1439 22 1698 23 2082 24 2371 25 2734