# A003756 (b-file synthesized from sequence entry)
1 1
2 0
3 24
4 54
5 492
6 1944
7 11976
8 57024
9 313440
10 1587168
11 8417472
12 43483392
13 227995008
14 1185394176
15 6192642048
16 32263570944
17 168350991360
18 877689686016
19 4578049517568
20 23872537976832
21 124504626978816
22 649282059657216
23 3386128302882816
24 17658788068196352