local mod = 998244353
local mfl = math.floor
local function bmul(x, y)
  local x0, y0 = x % 31596, y % 31596
  local x1, y1 = mfl(x / 31596), mfl(y / 31596)
  return (x1 * y1 * 62863 + (x1 * y0 + x0 * y1) * 31596 + x0 * y0) % mod
end
local function badd(x, y)
  return (x + y) % mod
end

local function bsub(x, y)
  return x < y and x - y + mod or x - y
end

local function modpow(src, pow)
  local res = 1
  while 0 < pow do
    if pow % 2 == 1 then
      res = bmul(res, src)
      pow = pow - 1
    end
    src = bmul(src, src)
    pow = mfl(pow / 2)
  end
  return res
end

local function modinv(src)
  return modpow(src, mod - 2)
end
local p2 = {2}
for i = 2, 1000010 do
  p2[i] = badd(p2[i - 1], p2[i - 1])
end
local function getp2(i)
  if i == 0 then return 1 else return p2[i] end
end

local n = io.read("*n")
local a = {}
for i = 1, n do
  a[i] = io.read("*n") % mod
end
local ret = 0
for i = n, 1, -1 do
  if 1 < i then
    local v = badd(getp2(i - 1), bmul(i - 1, getp2(i - 2)))
    v = bmul(v, getp2(n - i))
    ret = badd(ret, bmul(a[i], v))
  else
    ret = badd(ret, bmul(a[i], getp2(n - 1)))
  end
end
print(ret)