Sum of squares of divisors

November 10, 2012

The divisors of 6 are 1,2,3 and 6. The sum of the squares of these numbers is 1+4+9+36=50.

Let sigma2(n) represent the sum of the squares of the divisors of n. Thus sigma2(6)=50.

Let SIGMA2 represent the summatory function of sigma2, that is SIGMA2(n)=∑sigma2(i) for i=1 to n. The first 6 values of SIGMA2 are: 1,6,16,37,63 and 113.

Find SIGMA2(10¹⁵) modulo 10⁹.

Written by gamwe6 who lives and works in San Francisco building useful things. You should follow him on Twitter

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