A119022 - OEIS

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A119022 as a simple table

n	a(n)
0	1
1	1
2	4
3	20
4	154
5	1302
6	12672
7	129558
8	1462890
9	17537234
10	223689128
11	2959757528
12	40637432332
13	573938538500
14	8324542177200
15	123276663007740
16	1861540558106490
17	28613268804680010
18	447616821726181800

[1,1,4,20,154,1302,12672,129558,1462890,17537234, 223689128,2959757528,40637432332,573938538500, 8324542177200,123276663007740,1861540558106490, 28613268804680010,447616821726181800]