/* in the name of Anton */

/*
  Compete against Yourself.
  Author - Aryan Choudhary (@aryanc403)
*/

#ifdef ARYANC403
    #include "/home/aryan/codes/PastCodes/template/header.h"
#else
    #pragma GCC optimize ("Ofast")
    #pragma GCC target ("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
    #pragma GCC optimize ("-ffloat-store")
    #include<iostream>
    #include<bits/stdc++.h>
    #define dbg(args...)
#endif

using namespace std;
#define fo(i,n)   for(i=0;i<(n);++i)
#define repA(i,j,n)   for(i=(j);i<=(n);++i)
#define repD(i,j,n)   for(i=(j);i>=(n);--i)
#define all(x) begin(x), end(x)
#define sz(x) ((lli)(x).size())
#define pb push_back
#define mp make_pair
#define X first
#define Y second
#define endl "\n"

typedef long long int lli;
typedef long double mytype;
typedef pair<lli,lli> ii;
typedef vector<ii> vii;
typedef vector<lli> vi;


const auto start_time = std::chrono::high_resolution_clock::now();
void aryanc403()
{
#ifdef ARYANC403
auto end_time = std::chrono::high_resolution_clock::now();
std::chrono::duration<double> diff = end_time-start_time;
    cerr<<"Time Taken : "<<diff.count()<<"\n";
#endif
}

const lli INF = 0xFFFFFFFFFFFFFFFL;

lli seed;
mt19937 rng(seed=chrono::steady_clock::now().time_since_epoch().count());
inline lli rnd(lli l=0,lli r=INF)
{return uniform_int_distribution<lli>(l,r)(rng);}

class CMP
{public:
bool operator()(ii a , ii b) //For min priority_queue .
{    return ! ( a.X < b.X || ( a.X==b.X && a.Y <= b.Y ));   }};

void add( map<lli,lli> &m, lli x,lli cnt=1)
{
    auto jt=m.find(x);
    if(jt==m.end())         m.insert({x,cnt});
    else                    jt->Y+=cnt;
}

void del( map<lli,lli> &m, lli x,lli cnt=1)
{
    auto jt=m.find(x);
    if(jt->Y<=cnt)            m.erase(jt);
    else                      jt->Y-=cnt;
}

bool cmp(const ii &a,const ii &b)
{
    return a.X<b.X||(a.X==b.X&&a.Y<b.Y);
}

const lli mod = 1000000007L;
// const lli maxN = 1000000007L;
const lli L=33;
// typedef bitset<N> bt;

    lli T,n,i,j,k,in,cnt,l,r,u,v,x,y;
    lli m;
    string s;
    vi a;
    set<ii> b,c;
    // unordered_set<ii> b,c;
    // vii b,c;
    //priority_queue < ii , vector < ii > , CMP > pq;// min priority_queue .

bool get(const ii &a,lli x)
{
    if(x<=50)
        return a.X&(1LL<<x);
    x-=50;
    return a.Y&(1LL<<x);
}

void se(ii &a,lli x)
{
    if(x<=50)
        a.X|=(1LL<<x);
    else
    {
        x-=50;
        a.Y|=(1LL<<x);
    }
}

lli solve(ii msk)
{
    lli ans=0;
    for(lli k=1;k<=L&&k<=n;++k)
    {
        if(get(msk,k))
            continue;
        ans+=a[k];
    }

    for(lli k=L+1;k<=n;++k)
    {
        if(get(msk,k))
            continue;
        if(a[k]>=0)
        {
            ans+=a[k];
            continue;
        }

        lli ct=a[k];
        if(2*k<=n&&!get(msk,2*k))
            ct+=a[2*k];
        if(ct>=0)
            ans+=ct;
        se(msk,k);
        if(2*k<=n)
            se(msk,2*k);
    }
    return ans;
}

int main(void) {
    ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
    // freopen("txt.in", "r", stdin);
    // freopen("txt.out", "w", stdout);
// cout<<std::fixed<<std::setprecision(35);
// cin>>T;while(T--)
{

    cin>>n;
    a.clear();a.reserve(n+1);
    a.pb(0);
    fo(i,n)
    {
        // in=rnd(-100,100);
        cin>>in;
        a.pb(in);
    }

    b.insert(ii());
    // b.pb(ii());

    for(lli k=1;k<=31&&k<=n;++k)
    {
        c=b;
        ii cur;
        for(lli j=k;j<=n;j+=k)
            se(cur,j);
        for(auto x:b)
            c.insert({x.X|cur.X,x.Y|cur.Y});
        c.swap(b);
    }

    dbg(b);
    lli ans=0;
    for(const auto &cur:b)
    {
        ans=max(ans,solve(cur));
        ans=max(ans,solve(mp(cur.X|4294967296LL,cur.Y|70368744194048LL)));
        ans=max(ans,solve(mp(cur.X|8589934592LL,cur.Y|562949953486848LL)));
        ans=max(ans,solve(mp(cur.X|12884901888LL,cur.Y|633318697680896LL)));
    }
    cout<<ans<<endl;
}   aryanc403();
    return 0;
}


Measured memory_bytes: 168660