#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;
template <class T>
using MaxHeap = std::priority_queue<T>;
template <class T>
using MinHeap = std::priority_queue<T, vector<T>, greater<T>>;
#define rep2(i, n) for (ll i = 0; i < (n); i++)
#define rep3(i, l, r) for (ll i = (l); i < (r); i++)
#define rrep2(i, n) for (ll i = n; i-- > 0;)
#define rrep3(i, r, l) for (ll i = (r); i-- > (l);)
#define overload(a, b, c, d, ...) d
#define rep(...) overload(__VA_ARGS__, rep3, rep2)(__VA_ARGS__)
#define rrep(...) overload(__VA_ARGS__, rrep3, rrep2)(__VA_ARGS__)
#define all(x) begin(x), end(x)
bool chmin(auto& lhs, auto rhs) {
    return lhs > rhs ? lhs = rhs, 1 : 0;
}
bool chmax(auto& lhs, auto rhs) {
    return lhs < rhs ? lhs = rhs, 1 : 0;
}
struct IOIO {
    IOIO() {
        std::cin.tie(0)->sync_with_stdio(0);
    }
} ioio;

void solve() {
    int n;
    cin >> n;
    vector<ll> a(n);
    rep(i, n) cin >> a[i];
    const int MAX = 2e5 + 10;
    ll ans = 0;
    int COUNT[10 * MAX]{};
    const int OFFSET = 5 * MAX;
    rep(d, 1, MAX) {
        rep(i, n) {
            if ((i + 1) * d >= 2 * MAX) break;
            int require = (i + 1) * d - a[i];
            ans += COUNT[OFFSET + require];
            COUNT[OFFSET - require]++;
        }
        rep(i, n) {
            if ((i + 1) * d >= 2 * MAX) break;
            int require = (i + 1) * d - a[i];
            COUNT[OFFSET - require]--;
        }
    }
    cout << ans << '\n';
}

int main() {
    int t = 1;
    //  cin >> t;
    while (t--) solve();
}