# A089847 (b-file synthesized from sequence entry) 0 1 1 1 2 2 3 3 4 8 5 24 6 72 7 231 8 764 9 2574 10 8840 11 30796 12 108528 13 386308 14 1386756 15 5014575 16 18249120 17 66786738 18 245642760 19 907513530 20 3366215688 21 12531502620 22 46805032560 23 175341580596 24 658674458208 25 2480584898700 26 9363748625972