#include <bits/stdc++.h>
using namespace std;
const int INF = 2034567891;
const long long int INF64 = 4234567890123456789ll;
long long nc3(long long v) { return (v * (v - 1ll) * (v - 2ll)) / 6ll; }
long long nc2(long long v) { return (v * (v - 1ll)) / 2ll; }
long long int gcd(long long int a, long long int b) {
  return (b == 0 ? a : gcd(b, a % b));
}
long long int lcm(long long int a, long long int b) {
  return (a * (b / gcd(a, b)));
}
const int N = 10 + 2e5;
bool isprime(long long int n) {
  if (n < 2) return 0;
  if (n == 2) return 1;
  if (n % 2 == 0) return 0;
  for (long long int i = 3; i * i <= n; i++)
    if (n % i == 0) return 0;
  return 1;
}
double dist(pair<long long int, long long int> p1,
            pair<long long int, long long int> p2) {
  return (p1.first - p2.first) * (p1.first - p2.first) +
         (p1.second - p2.second) * (p1.second - p2.second);
}
long long int power(long long int x, long long int y) {
  long long int ans = 1;
  while (y > 0) {
    if (y & 1) ans = (ans * x);
    x = (x * x);
    y /= 2;
  }
  return ans;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  long long int n;
  cin >> n;
  long long int a[n + 1];
  a[0] = 0;
  for (long long int i = 1; i <= n; i++) cin >> a[i];
  set<long long int> s;
  long long int len = 1;
  for (long long int i = 1; i <= n; i++) {
    long long int x[i];
    for (long long int j = 0; j < i; j++) x[j] = INF;
    long long int f = 0;
    for (long long int j = 1; j <= n; j++) {
      long long int tmp = a[j] - a[j - 1];
      long long int idx = (j - 1) % i;
      if (x[idx] != INF && x[idx] != tmp) {
        f = 1;
        break;
      }
      x[idx] = tmp;
    }
    if (!f) s.insert(i);
  }
  cout << s.size() << endl;
  for (auto i : s) cout << i << " ";
}
