# A149428 (b-file synthesized from sequence entry) 0 1 1 1 2 4 3 13 4 44 5 156 6 560 7 2049 8 7684 9 28772 10 108368 11 412396 12 1573776 13 6029488 14 23226176 15 89573577 16 346281380 17 1343190436 18 5216949776 19 20296197484 20 79131832976 21 308798743728 22 1206495306816 23 4720960267204 24 18487515792272 25 72463886990864 26 284340829780288 27 1116404838166192 28 4386449721693760