你输入的题目有几种结果：
1,cn=(4n-3)*[3/(2ⁿ)]
2.cn=(4n-3)*(1.5)ⁿ
3.cn=(4n-3)*(三分之二的)ⁿ
4 ,cn=(4n-3)*[(1/3)*2ⁿ]第一个cn=(4n-3)*[3/(2ⁿ)]

设存在一个n,
{cn>c(n+1)
{cn≥c(n-1)
.......................................
{(4n-3)*[3/(2ⁿ)]>(4n+1)*[3/(2*2ⁿ)]

{(4n-3)*[3/(2ⁿ)]≥(4n-7)*[2*3/(2ⁿ)]

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{(4n-3)*[1/(1)]>(4n+1)*[1/(2)]

{(4n-3)*[1/(1)]≥(4n-7)*[2*1/(1)]
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{8n-6>4n+1
{4n-3≥8n-14
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7/4n=2