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

const int K = 18, N = 1<<K, M = 1e9+7;
int prod[N][K];
int a[N];

vector<pair<int, int>> vp[N];

void add(int x, int z, int mul) {
    assert(vp[x].empty() || vp[x].back().first <= z);
    if (vp[x].empty() || vp[x].back().first < z)      vp[x].push_back({z, mul});
    else {
        vp[x].back().second += mul;
        if (vp[x].back().second >= M) vp[x].back().second -= M;
    }
}

int rgt[N];

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    int k;
    cin>>k;

    int L = 1<<(k-1), R = 2*L-1;

    for (int i=L; i<=R; i++) {
        prod[i][0] = i;
        for (int j=1; j<k; j++) {
            prod[i][j] = (1LL*prod[i][j-1]*(i>>j))%M;
        }
    }


    for (int i=L; i<2*L; i++) {
        int x;
        cin>>x;
        a[i] = x+L-1;
    }

     for (int k1=k-1; k1>=0; k1--) {
        for (int k2=k-1; k2>=0; k2--) {
            for (int i=L; i<2*L; i++) {
                int x = a[i];
                int pr = (1LL*prod[i][k1]*prod[x][k2])%M;

                int a1 = (i>>k1), a2 = (x>>k2);
                add(a2, a1, pr);
            }
        }
    }

    long long ans = 0;
    for (int i=1; i<=L; i++) {
        int ll = 2*i, rr = 2*i+1;

        for (auto pr: vp[rr])       rgt[pr.first] = pr.second;

        for (auto pr: vp[ll]) {
            int x = pr.first;
            if (x == 1) continue;
            long long con = (1LL*pr.second*rgt[x^1])%M;
            con = (con*i)%M;
            con = (con*(x>>1))%M;
            ans += con;
        }

        for (auto pr: vp[rr])       rgt[pr.first] = 0;
    }
    cout<<ans%M<<endl;
}
