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一同学在电脑中打出如下若干个圈:○●○○●○○○●○○○○●○○○○○●…若将此...
一同学在电脑中打出如下若干个圈:○●○○●○○○●○○○○●○○○○○●…若将此若干个圈依此规律继续下去,得到一系列的圈,那么在前120个圈中的●的个数是 .
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