/**
 * code generated by JHelper
 * More info: https://github.com/AlexeyDmitriev/JHelper
 * @author Gosu_Hiroo
 */

#include <iostream>
#include <fstream>

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
#define tr(container, it) \
        for (auto it = container.begin(); it != container.end(); it++)
#define scontains(c, x) ((c).find(x) != (c).end())   //O(log n)
#define contains(c, x) (find((c).begin(),(c).end(),x) != (c).end()) //O(n)
#define pll pair<ll,ll>
#define pii pair<int,int>
#define mll map<ll,ll>
#define intv(x, a, b)((x)>=a && (x)<=b)
#define  rep(i, _begin, _end) for (__typeof(_end) end = _end, begin = _begin,  i = (begin) - ((begin) > (end)); i != (end) - ((begin) > (end)); i += 1 - 2 * ((begin) > (end)))
#define  _for(i, end) for (__typeof(end) i = 0, _len = (end); i < (_len); i += 1)
#define all(x) (x).begin(),(x).end()
#define SZ(x) ((int)(x).size())
#define F first
#define S second
#define y0 y3487465
#define y1 y8687969
#define j0 j1347829
#define j1 j234892
#define what_is(x) cerr << #x << " is " << x << endl;
#define error(args...) { string _s = #args; replace(_s.begin(), _s.end(), ',', ' '); stringstream _ss(_s); istream_iterator<string> _it(_ss); err(_it, args); }
#define mod(x, m) ((((x) % (m)) + (m)) % (m))
#define bit(n) (1LL<<(n))
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() );
#define readint ({int t;cin >> t;t;})
const double PI = 2 * acos(.0);
const int INF = 0x3f3f3f3f;
const ll LLINF = 1000000000000000005LL;;
const ll MOD = (ll) (1e9) + 7;
void _mod(ll &x){x = mod(x, MOD);}
//const ll MOD = (ll) 998244353 ;
const double EPS = 1e-10;
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};

void err(istream_iterator<string> it) {}
template<typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
    cerr << *it << " = " << a << endl;
    err(++it, args...);
}

template<typename A, size_t N, typename T>
void Fill(A (&array)[N], const T &val) {
    std::fill((T *) array, (T *) (array + N), val);
}

template <typename T>
ostream& operator << (ostream& os, const vector<T> V) {
    for(auto v : V)os << v << " ";
    return os;
}

template <typename T>
ostream& operator << (ostream& os, const set<T> V) {
    for(auto v : V)os << v << " ";
    return os;
}

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

//#define int ll

class DPreparingBoxes {
public:
    int N;
    int A[202020];
    int B[202020];
void solve(std::istream& cin, std::ostream& cout) {
    cin >> N;
    _for(i,N)cin >> A[i+1];
    Fill(B, -1);
    rep(i,N+1,1){
        int t = A[i];
        for(int j = N/i*i;j > i;j -= i){
            if(B[j] != -1)t ^= B[j];
//            else {
//                B[j] = t;
//                if(j - i > 0)cerr << "ERRORRRRRRRRRRRRRRRR" << endl;
//            }
        }
        if(B[i] != -1 && B[i] !=t ){
            cout << -1 << endl;
            return;
        }
        else {
            B[i] = t;
        }
    }

    int cnt = 0;
    _for(i,N)if(B[i+1])cnt ++;
    cout << cnt << endl;
    _for(i,N){
        if(B[i+1])cout << i+1 << endl;
    }

}


};


#undef int
int main() {


	DPreparingBoxes solver;
	std::istream& in(std::cin);
	std::ostream& out(std::cout);
	in.tie(0); ios::sync_with_stdio(0); out<<fixed<<setprecision(20);
	solver.solve(in, out);
	return 0;
}


Measured memory_bytes: 2560