# A175596 (b-file synthesized from sequence entry)
1 1
2 3
3 9
4 54
5 162
6 1458
7 4374
8 43740
9 262440
10 2361960
11 7085880
12 127545840
13 382637520
14 3443737680
15 30993639120
16 464904586800
17 1394713760400
18 25104847687200
19 75314543061600
20 1355661775108800
21 12200955975979200
22 109808603783812800
23 329425811351438400
24 9882774340543152000
25 59296646043258912000
26 533669814389330208000
27 5336698143893302080000
28 96060566590079437440000
29 288181699770238312320000
30 7780905893796434432640000