# A234854 (b-file synthesized from sequence entry)
1 1
2 4
3 18
4 96
5 624
6 4896
7 45072
8 474624
9 5619456
10 73903104
11 1069106688
12 16872800256
13 288483876864
14 5311773904896
15 104789944829952
16 2205099306123264
17 49302137885884416
18 1167150882577711104
19 29165495002777387008
20 767163772371852066816
21 21188300138891474632704