n = int(input())
a = list(map(int, input().split()))
MOD = 998244353


ptn = pow(2, n, MOD)
inv2 = pow(2, MOD - 2, MOD)
ans = 0
for i in range(n):
    length = i + 1
    ans += a[i] * (ptn * inv2) * (inv2 * (length + 1))
print(ans % MOD)