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A270462型作为一个简单的表

n个a(n)
01
14
224
120
4612
52532
610800
745380
8182768
9728848
102917132
1111771140
1247229148
13188138496
14753562420
153021549192

[1,4,24,120,612,2532,10800,45380,182768,728848,2917132,11771140,47229148,188138496,753562420,3021549192]