N = gets.chop.to_i
a = gets.chop.split.map(&:to_i)

if N == 1
  puts a[0]
  exit
end

MOD = 10**9 + 7
MAX = N + 100

def fact_mod()
  $fact = Array.new(MAX, 0)
  $fact[0] = 1
  for i in 1..MAX - 1
    $fact[i] = $fact[i - 1] * i % MOD
  end
end

def inv_mod()
  $inv = Array.new(MAX, 0)
  $inv[0] = 1
  $inv[1] = 1
  for i in 2..MAX - 1
    $inv[i] = MOD - $inv[MOD % i] * (MOD / i) % MOD
  end
end

def fact_inv_mod()
  $factInv = Array.new(MAX, 0)
  $factInv[0] = 1
  for i in 1..MAX - 1
    $factInv[i] = $factInv[i - 1] * $inv[i] % MOD
  end
end


def make_mod()
  fact_mod()
  inv_mod()
  fact_inv_mod()
end

def comb_mod(n, k)
  if n < k
    return 0
  end
  if n < 0 || k < 0
    return 0
  end
  return $fact[n] * (($factInv[k] * $factInv[n - k]) % MOD) % MOD
end

make_mod()
ans = 0
for i in 1..N
  ans += a[i - 1] * (comb_mod(N - 1, i - 1) % MOD)
end
puts (ans % MOD).to_i