# A204446 (b-file synthesized from sequence entry) 1 1 2 1 3 3 4 9 5 34 6 116 7 792 8 4752 9 32304 10 202320 11 1991952 12 17927568 13 175473216 14 1613364480 15 20695108608 16 248341303296 17 3173837230080 18 38575603814400 19 610011772416000 20 9150176586240000 21 144343174487040000 22 2183607168215040000