0%

Problem 694


Problem 694


Cube-full Divisors

A positive integer n is considered cube-full, if for every prime p that divides n, so does p3. Note that 1 is considered cube-full.

Let s(n) be the function that counts the number of cube-full divisors of n. For example, 1, 8 and 16 are the three cube-full divisors of 16. Therefore, s(16)=3.

Let S(n) represent the summatory function of s(n), that is S(n)=i=1ns(i).

You are given S(16)=19, S(100)=126 and S(10000)=13344.

Find S(1018).


满立方约数

考虑正整数n,若对于任意整除n的质数p,总有p3也整除n,则称n满立方数。作为特例,1也是满立方数。

s(n)n的所有约数中满立方数的数目。例如,16的约数中有1816三个满立方数,因此s(16)=3

S(n)s(n)的部分和函数,也即S(n)=i=1ns(i)

已知S(16)=19S(100)=126S(10000)=13344

S(1018)


0 comments
Anonymous
Markdown is supported

Be the first person to leave a comment!