import java.io.*; import java.util.NoSuchElementException; public class Main_yukicoder797 { private static Scanner sc; private static Printer pr; private static void solve() { final int MOD = 1_000_000_007; int n = sc.nextInt(); int[] a = new int[n]; for (int i = 0; i < n; i++) { a[i] = sc.nextInt(); } PC pc = new PC(n, MOD); long ans = 0; for (int i = 0; i < n; i++) { ans += (long)a[i] * pc.C(n - 1, i); ans %= MOD; } pr.println(ans); } static class PC { // MOD must be a prime number. int MOD; // fact[i] : i! % MOD long[] fact; // ifact[i] : 1/i! % MOD long[] ifact; PC(int size, int MOD) { // O(size) // n=sizeまでのnCrを求める。 // nHrはn+r-1Crになってしまうので注意 this.MOD = MOD; fact = new long[size + 1]; fact[0] = 1; for (int i = 1; i <= size; i++) { fact[i] = fact[i - 1] * i % MOD; } ifact = new long[size + 1]; int loop = MOD - 2; long x = fact[size]; ifact[size] = 1; while (loop > 0) { if (loop % 2 == 1) { ifact[size] = ifact[size] * x % MOD; } x = x * x % MOD; loop /= 2; } for (int i = size - 1; i >= 0; i--) { ifact[i] = ifact[i + 1] * (i + 1) % MOD; } } // 組合せの数 int C(int n, int r) { if (r > n) { return 0; } return (int)(((fact[n] * ifact[n - r]) % MOD) * ifact[r] % MOD); } // 順列 int P(int n, int r) { if (r > n) { return 0; } return (int)((fact[n] * ifact[n -r]) % MOD); } // 重複組み合わせ // 異なるn種のものから重複を許してr個を選ぶ場合の数 // 0個の種類もあり得る int H(int n, int r) { if (n == 0 && r == 0) { return 1; } return C(n + r - 1, r); } // 組合せの数(nが大きいとき) // O(r)で求めることができる。rはsizeの大きさまで int C2(long n, int r) { long ret = ifact[r]; for (int i = 1; i <= r; i++) { long tmp = (n - r + i) % MOD; ret = (ret * tmp) % MOD; } return (int)ret; } // 第2種スターリング数 // n人をちょうどr個のグループに分ける(グループの区別はなし) // グループの区別をする場合はr!S(n,r)。全射の場合の数と同義 // O(r log n) int S(long n, int r) { //全射の場合の数を包除原理を使って求めて、1/r!をかける。 long ret = 0; for (int i = 1; i <= r; i++) { long tmp = (r - i) % 2 == 0 ? 1 : -1; tmp *= pow(i, n) * C(r, i) % MOD; ret = (ret + tmp + MOD) % MOD; } ret = ret * ifact[r] % MOD; return (int)ret; } long pow(int a, long n) { long loop = n; long ret = 1; long x = a; while (loop > 0) { if (loop % 2 == 1) { ret = ret * x % MOD; } x = x * x % MOD; loop /= 2; } return ret; } // 組合せの数 // パスカルの三角形MODなし // 限界:n=66 : 66C33=7219428434016265740 private final static int LIMIT = 66; private static int to; private static long[][] cache; static long CLong(int n, int r) { if (r > n) { return 0; } if (n > LIMIT) { throw new IllegalArgumentException(Integer.toString(n)); } if (cache == null) { cache = new long[LIMIT + 1][]; cache[0] = new long[1]; cache[0][0] = 1; to = 0; } if (cache[n] == null) { for (int i = to + 1; i <= n; i++) { cache[i] = new long[i + 1]; for (int j = 0; j <= i; j++) { if (j == 0 || j == i) { cache[i][j] = 1; } else { if (Long.MAX_VALUE - cache[i - 1][j - 1] < cache[i - 1][j]) { throw new IllegalArgumentException("Overflow"); } else { cache[i][j] = cache[i - 1][j - 1] + cache[i - 1][j]; } } } } to = n; } return cache[n][r]; } } // --------------------------------------------------- public static void main(String[] args) { sc = new Scanner(System.in); pr = new Printer(System.out); solve(); pr.close(); sc.close(); } static class Scanner { BufferedReader br; Scanner (InputStream in) { br = new BufferedReader(new InputStreamReader(in)); } private boolean isPrintable(int ch) { return ch >= '!' && ch <= '~'; } private boolean isCRLF(int ch) { return ch == '\n' || ch == '\r' || ch == -1; } private int nextPrintable() { try { int ch; while (!isPrintable(ch = br.read())) { if (ch == -1) { throw new NoSuchElementException(); } } return ch; } catch (IOException e) { throw new NoSuchElementException(); } } String next() { try { int ch = nextPrintable(); StringBuilder sb = new StringBuilder(); do { sb.appendCodePoint(ch); } while (isPrintable(ch = br.read())); return sb.toString(); } catch (IOException e) { throw new NoSuchElementException(); } } int nextInt() { try { // parseInt from Integer.parseInt() boolean negative = false; int res = 0; int limit = -Integer.MAX_VALUE; int radix = 10; int fc = nextPrintable(); if (fc < '0') { if (fc == '-') { negative = true; limit = Integer.MIN_VALUE; } else if (fc != '+') { throw new NumberFormatException(); } fc = br.read(); } int multmin = limit / radix; int ch = fc; do { int digit = ch - '0'; if (digit < 0 || digit >= radix) { throw new NumberFormatException(); } if (res < multmin) { throw new NumberFormatException(); } res *= radix; if (res < limit + digit) { throw new NumberFormatException(); } res -= digit; } while (isPrintable(ch = br.read())); return negative ? res : -res; } catch (IOException e) { throw new NoSuchElementException(); } } long nextLong() { try { // parseLong from Long.parseLong() boolean negative = false; long res = 0; long limit = -Long.MAX_VALUE; int radix = 10; int fc = nextPrintable(); if (fc < '0') { if (fc == '-') { negative = true; limit = Long.MIN_VALUE; } else if (fc != '+') { throw new NumberFormatException(); } fc = br.read(); } long multmin = limit / radix; int ch = fc; do { int digit = ch - '0'; if (digit < 0 || digit >= radix) { throw new NumberFormatException(); } if (res < multmin) { throw new NumberFormatException(); } res *= radix; if (res < limit + digit) { throw new NumberFormatException(); } res -= digit; } while (isPrintable(ch = br.read())); return negative ? res : -res; } catch (IOException e) { throw new NoSuchElementException(); } } float nextFloat() { return Float.parseFloat(next()); } double nextDouble() { return Double.parseDouble(next()); } String nextLine() { try { int ch; while (isCRLF(ch = br.read())) { if (ch == -1) { throw new NoSuchElementException(); } } StringBuilder sb = new StringBuilder(); do { sb.appendCodePoint(ch); } while (!isCRLF(ch = br.read())); return sb.toString(); } catch (IOException e) { throw new NoSuchElementException(); } } void close() { try { br.close(); } catch (IOException e) { // throw new NoSuchElementException(); } } } static class Printer extends PrintWriter { Printer(OutputStream out) { super(out); } } }