# A129772 (b-file synthesized from sequence entry) 0 1 1 2 2 6 3 16 4 48 5 140 6 420 7 1248 8 3744 9 11200 10 33600 11 100704 12 302112 13 906056 14 2718168 15 8153664 16 24460992 17 73380480 18 220141440 19 660416832 20 1981250496 21 5943729088 22 17831187264 23 53493494592 24 160480483776 25 481441249920 26 1444323749760