A197209 - OEIS

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A197209 as a simple table

n	a(n)
2	3
3	24
4	180
5	1320
6	9660
7	70896
8	522648
9	3871440
10	28809990
11	215318400
12	1615579680
13	12165491520
14	91905439080
15	696359055840
16	5290416835440
17	40291036122528
18	307537305284574
19	2352216447006480
20	18024996856976760

[3,24,180,1320,9660,70896,522648,3871440,28809990, 215318400,1615579680,12165491520,91905439080, 696359055840,5290416835440,40291036122528, 307537305284574,2352216447006480, 18024996856976760]