func_code_string: #include <bits/stdc++.h>   using namespace std;   long long dp[5000010], f[5000010];   int main() {     long long t, l, r, i, j, a, b, mod, ans, k = 1, final = 0;     mod = 1e9 + 7;     scanf( %lld %lld %lld , &t, &l, &r);     for (i = 2; i <= r; i++) {       if (dp[i] == 0) {         for (j = i; j <= r; j += i)           if (!dp[j]) dp[j] = i;       }       a = dp[i];       b = i / dp[i];       if (b == 1)         f[i] = (i * (i - 1) / 2) % mod;       else         f[i] = (b * f[a] + f[b]) % mod;       if (i >= l) {         final = (final + k * f[i]) % mod;         k = (k * t) % mod;       }     }     printf( %lld n , final);     return 0;   }   