# A135490 (b-file synthesized from sequence entry) 0 1 1 6 2 30 3 162 4 886 5 4932 6 27714 7 157018 8 894942 9 5126268 10 29481732 11 170128850 12 984577446 13 5712117772 14 33210790018 15 193456179430 16 1128789904110 17 6596174575548 18 38596967873100 19 226120320617484 20 1326180436400932