# A018088 (b-file synthesized from sequence entry) 0 1 1 2 2 4 3 8 4 15 5 30 6 58 7 114 8 225 9 443 10 871 11 1715 12 3375 13 6642 14 13071 15 25724 16 50625 17 99629 18 196070 19 385863 20 759375 21 1494442 22 2941047 23 5787950 24 11390625 25 22416632 26 44115701 27 86819244 28 170859375