# A308520 (b-file synthesized from sequence entry) 0 1 1 3 2 9 3 27 4 84 5 287 6 1116 7 4984 8 25368 9 145277 10 924684 11 6475018 12 49464756 13 409371731 14 3648595216 15 34841512504 16 354892721168 17 3840839273849 18 44012775982132 19 532368664987942 20 6778328366073724 21 90619575089479631 22 1269184691838666152 23 18583725601041230532