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#include <stdio.h>
#include <math.h>
#define MAX 9999
int firstdiv(int n)
{
int i;
int q=ceil(sqrt(n));
for (i=2;i<=q;++i){
if (n%i==0)
return i;
}
return n;
}
int divexp(int n,int d)
{
int dd=1;
while (n%d==0){
n/=d;
dd*=d;
}
return dd;
}
int sumdiv(int n)
{
if (n==1)
return 1;
int fd=firstdiv(n);
int fdexp=divexp(n,fd);
return sumdiv(n/fdexp)*(fdexp*fd-1)/(fd-1);
}
int main()
{
int d[MAX+1],i,sum=0;
for (i=1;i<=MAX;++i){
d[i]=sumdiv(i)-i;
}
for (i=1;i<=MAX;++i){
if (i<d[i] && d[i]<=MAX && i==d[d[i]]){
sum+=i+d[i];
}else if (d[i]>MAX && sumdiv(d[i])-d[i]==i){
sum+=i;
}
}
printf("%d\n",sum);
return 0;
}
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