A190984-OEIS公司

A190984号作为一个简单的表

n个	a（n）
0	0
1	1
2	9
三	74
4	603
5	4909
6	39960
7	325277
8	2647773
9	21553018
10	175442751
11	1428113633
12	11624923440
13	94627515529
14	770273175681
15	6270065972426
16	51038681522067
17	415457671891621
18	3381848276370120
19	27528430784089733
20	224082939122216757
21	1824047436611322682

[0,1,9,74,603,4909,39960,325277,2647773,21553018,175442751,1428113633,11624923440,94627515529,770273175681,6270065972426,51038681522067,415457671891621,3381848276370120,27528430784089733,224082939122216757,1824047436611322682]