# A109319 (b-file synthesized from sequence entry) 0 1 1 2 2 5 3 15 4 55 5 235 6 1119 7 5775 8 31663 9 182087 10 1087927 11 6706823 12 42433735 13 274403575 14 1807700679 15 12099813111 16 82113733447 17 563992581079 18 3914861387495 19 27429176467703 20 193781828188615 21 1379223584026967