import sys
input = sys.stdin.readline

N = int(input())
a = list(map(int, input().split()))
ans = 0
MOD = 998244353

for i in range(N):
    ans += pow(2, i-1, MOD)*(i+2)*pow(2, N-i-1, MOD)*a[i]
    ans %= MOD

print(ans)