n = int(input())
A = list(map(int, input().split()))
mod = 998244353

# ((k+1)x+1)(x+1)^(k-1)=kC0+2kC1x+3kC2x^2+...
ans = 0
for i in range(n):
    a = A[i]
    if i == 0:
        res = 1
    else:
        res = (i + 2) * pow(2, i - 1, mod) % mod
    if i == n - 1:
        res *= 1
    else:
        res *= pow(2, n - i - 2, mod)
        res %= mod
    ans += res * a % mod
    ans %= mod
print(ans)