from math import comb

mod = 998244353
n = int(input())
a = [*map(int, input().split())]
ans = 0
for i, v in enumerate(a):
    res = 0
    if i < n - 1:
        for j in range(i + 1):
            res = (res + comb(i, j) * (j + 1) * v) % mod
        res = (res * pow(2, n - 2 - i, mod)) % mod
    else:
        for j in range(n):
            res = (res + comb(n - 1, j) * (j + 1) * v) % mod
    ans = (ans + res) % mod
print(ans)