# A013183 (b-file synthesized from sequence entry)
0 1
1 2
2 4
3 9
4 24
5 105
6 630
7 4095
8 27720
9 235305
10 2353050
11 24792075
12 267567300
13 3350672325
14 46909412550
15 682570263375
16 10103827734000
17 167108397080625
18 3007951147451250
19 55823919598321875
20 1049953727680357500