#Java 8, 151 bytes
n->{int r=0,i=10000;for(;i-->0;r+=c(i)<n?1:0);return r;}int c(int n){int i=(int)Math.sqrt(n);for(;i>0;i--)if(n%i<1){i=n/i-i;break;}return i<0?-i:i;}
Can definitely be golfed by not having a separate method and merging the two for-loops, but still have to figure this out. This will do for now.
Explanation:
n->{ // Method with integer as parameter and return-type
int r=0, // Result-integer
i=10000; // Index-integer starting at 10,000
for(;x-->0; // Loop from 10,000 down to 0
r+=c(x)<n? // If the MaxMin-Divisor Pair's difference is lower than the input:
1 // Add 1 to the result
: // Else:
0 // Leave the result the same
); // End of loop
return r; // Return the result
} // End of method
int c(int n){ // Separate method with integer as parameter and return-type
int i=(int)Math.sqrt(n);
// Index-integer starting at the square-root of the input
for(;i>0;i--) // Loop down to 0
if(n%i<1){ // If the input is divisible by the current index-integer
i=n/i-i; // Subtract the MaxMin Divisor pair from each other
break; // And leave the loop
}
// End of loop (implicit / single-line body)
return i<0? // If the resulting MaxMin Divisor was negative:
-i // Return its positive equivalent
: // Else (it was already positive)
i; // Simply return it
} // End of separated method