# A057497 (b-file synthesized from sequence entry) 1 1 2 1 3 1 4 2 5 6 6 17 7 13 8 17 9 30 10 60 11 555 12 990 13 1616 14 2168 15 2467 16 2648 17 2294 18 1892 19 1283 20 810