A002520 - OEIS

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A002520 as a simple table

n	a(n)
0	1
1	0
2	0
3	2240
4	98280
5	1790208
6	19138560
7	141920640
8	805208040
9	3723722240
10	14651449344
11	50573436480
12	156717687840
13	443691198720
14	1162883174400
15	2851049534592
16	6596666916840
17	14509544394240
18	30507984568320

[1,0,0,2240,98280,1790208,19138560,141920640, 805208040,3723722240,14651449344,50573436480, 156717687840,443691198720,1162883174400, 2851049534592,6596666916840,14509544394240, 30507984568320]