Removing Cubes
Starting from a positive integer , at each step we subtract from the largest perfect cube not exceeding , until becomes .
For example, with the procedure ends in steps:
Let denote the number of steps of the procedure. Thus .
Let denote the sum of for all positive integers strictly less than .
For example, .
Find .
扣除立方数
从任意正整数开始,每一步依次扣除不超过的最大立方数,直到变为。
例如,从开始需要步:
记为从开始所需要的步数,因此。
记为所有严格小于的正整数所对应的之和。
例如,。
求。
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