A056621 - OEIS

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A056621 as a simple table

n	a(n)
2	8
3	66
4	600
5	5164
6	42872
7	346828
8	2754056
9	21549780
10	166626744
11	1275865332
12	9690096824
13	73090383120
14	548064459968
15	4088719617824
16	30367415294800
17	224659143155964
18	1656259765448200
19	12172580326973688

[8,66,600,5164,42872,346828,2754056,21549780, 166626744,1275865332,9690096824,73090383120, 548064459968,4088719617824,30367415294800, 224659143155964,1656259765448200, 12172580326973688]