A068142 - OEIS

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A068142 as a simple table

n	a(n)
0	21
1	105
2	210
3	630
4	25200
5	32004000
6	508031496000
7	128015872500032496000
8	3670698694547655407496988066168944000
9	10302657959650317880463349610273001290502485245258650172717840000

[21,105,210,630,25200,32004000,508031496000, 128015872500032496000, 3670698694547655407496988066168944000, 10302657959650317880463349610273001290502485245258\ 650172717840000]