# A047006 (b-file synthesized from sequence entry) 0 1 1 2 2 5 3 16 4 53 5 186 6 665 7 2430 8 8981 9 33556 10 126300 11 478468 12 1821677 13 6965726 14 26730639 15 102895388 16 397130997 17 1536321264 18 5955477230 19 23128018490 20 89962619148 21 350442078972 22 1366907765382 23 5337995113404 24 20868301796085