# A046105 (b-file synthesized from sequence entry)
0 1
1 2
2 16
3 120
4 882
5 6468
6 47680
7 354224
8 2652688
9 20008864
10 151853312
11 1158365824
12 8873772392
13 68219456080
14 526025997824
15 4066475337152
16 31505967787522
17 244574907064964
18 1901855959279776
19 14811829930479600
20 115514550050260068
21 901993060739459720