# A149838 (b-file synthesized from sequence entry) 0 1 1 2 2 4 3 12 4 36 5 100 6 340 7 1154 8 3650 9 13244 10 47744 11 161458 12 608218 13 2273268 14 8015248 15 30948100 16 118491620 17 429836776 18 1688856912 19 6578861670 20 24365169758 21 96986976404 22 382761606472 23 1440159264108 24 5790859055340 25 23087851622216 26 87959372528576 27 356553406654718 28 1433265655786694 29 5515870506340284