func_code_string: #include <bits/stdc++.h>   using namespace std;   const int MOD = (int)1e9 + 7;   const int FFTMOD = 119 << 23 | 1;   const int INF = (int)1e9 + 23111992;   const long long LINF = (long long)1e18 + 23111992;   const long double PI = acos((long double)-1);   const long double EPS = 1e-9;   inline long long gcd(long long a, long long b) {     long long r;     while (b) {       r = a % b;       a = b;       b = r;     }     return a;   }   inline long long lcm(long long a, long long b) { return a / gcd(a, b) * b; }   inline long long fpow(long long n, long long k, int p = MOD) {     long long r = 1;     for (; k; k >>= 1) {       if (k & 1) r = r * n % p;       n = n * n % p;     }     return r;   }   template <class T>   inline int chkmin(T& a, const T& val) {     return val < a ? a = val, 1 : 0;   }   template <class T>   inline int chkmax(T& a, const T& val) {     return a < val ? a = val, 1 : 0;   }   inline unsigned long long isqrt(unsigned long long k) {     unsigned long long r = sqrt(k) + 1;     while (r * r > k) r--;     return r;   }   inline long long icbrt(long long k) {     long long r = cbrt(k) + 1;     while (r * r * r > k) r--;     return r;   }   inline void addmod(int& a, int val, int p = MOD) {     if ((a = (a + val)) >= p) a -= p;   }   inline void submod(int& a, int val, int p = MOD) {     if ((a = (a - val)) < 0) a += p;   }   inline int mult(int a, int b, int p = MOD) { return (long long)a * b % p; }   inline int inv(int a, int p = MOD) { return fpow(a, p - 2, p); }   inline int sign(long double x) { return x < -EPS ? -1 : x > +EPS; }   inline int sign(long double x, long double y) { return sign(x - y); }   mt19937 mt(chrono::high_resolution_clock::now().time_since_epoch().count());   inline int mrand() { return abs((int)mt()); }   inline int mrand(int k) { return abs((int)mt()) % k; }   void chemthan() {     int C = 1e5 + 5;     vector<int> sp(C);     for (int i = (1); i < (C); ++i) sp[i] = i;     for (int i = (2); i < (C); ++i)       if (sp[i] == i) {         for (int j = i + i; j < C; j += i) {           chkmin(sp[j], i);         }       }     vector<int> mob(C, 1);     for (int i = (2); i < (C); ++i) {       int t = i;       int pv = -1;       while (1 < t) {         if (pv == sp[t]) {           mob[i] = 0;         }         mob[i] *= -1;         pv = sp[t];         t /= sp[t];       }     }     vector<vector<int> > dvs(C);     vector<vector<int> > dvs2(C);     for (int i = (1); i < (C); ++i) {       for (int j = i; j < C; j += i) {         dvs[j].push_back(i);         if (mob[j / i]) dvs2[j].push_back(i);       }     }     int n;     cin >> n;     vector<int> a(n);     vector<vector<int> > g(C);     for (int i = (0); i < (n); ++i) {       cin >> a[i];       for (int d : dvs[i + 1]) {         g[d].push_back(a[i]);       }     }     vector<int> c(C);     vector<int> f(C);     vector<int> x(C);     vector<int> y(C);     int res = 0;     for (int i = (1); i < (C); ++i)       if (int((g[i]).size())) {         vector<int> tmp2;         vector<int> tmp;         for (int u : g[i]) {           c[u] = 0;         }         for (int u : g[i]) {           if (!c[u]++) {             tmp2.push_back(u);           }         }         for (int u : tmp2) {           for (int d : dvs[u]) {             if (!f[d]) {               tmp.push_back(d);             }             f[d] += c[u];           }         }         for (int u : tmp) {           f[u] = mult(f[u], f[u]);         }         int sum = 0;         for (int u : tmp) {           for (int v : dvs2[u]) {             if (mob[u / v]) {               if (mob[u / v] == 1) {                 addmod(x[v], f[u]);               } else {                 submod(x[v], f[u]);               }             }           }         }         for (int u : tmp) {           addmod(sum, mult(x[u], u));         }         y[i] = sum;         for (int u : tmp) f[u] = x[u] = 0;       }     for (int i = (C)-1; i >= (1); --i) {       for (int j = i + i; j < C; j += i) {         submod(y[i], y[j]);       }       addmod(res, mult(i, y[i]));     }     cout << res <<   n ;   }   int32_t main(int32_t argc, char* argv[]) {     ios_base::sync_with_stdio(0), cin.tie(0);     if (argc > 1) {       assert(freopen(argv[1],  r , stdin));     }     if (argc > 2) {       assert(freopen(argv[2],  wb , stdout));     }     chemthan();     cerr <<   nTime elapsed:   << 1000 * clock() / CLOCKS_PER_SEC <<  ms n ;     return 0;   }   