# A058820 (b-file synthesized from sequence entry) 0 1 1 5 2 15 3 85 4 475 5 2501 6 13045 7 66965 8 341875 9 1736125 10 8789377 11 44389205 12 223796925 13 1126802885 14 5667555805 15 28483073133 16 143051171875 17 718060661765 18 3602769749125 19 18069618626645 20 90599060546905 21 454130626863845 22 2275813711825285 23 11402627696161685 24 57121117919938125