A104470 - OEIS

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A104470 as a simple table

n	a(n)
0	1
1	1
2	1
3	9
4	44
5	270
6	1938
7	15764
8	143776
9	1453302
10	16128420
11	194980478
12	2550746400
13	35904118874
14	541097840528
15	8693290587030
16	148324680742912
17	2678504175897990
18	51039398650102776
19	1023458322628129882

[1,1,1,9,44,270,1938,15764,143776,1453302, 16128420,194980478,2550746400,35904118874, 541097840528,8693290587030,148324680742912, 2678504175897990,51039398650102776, 1023458322628129882]