N = int(input())
A = list(map(int, input().split()))

def func2(k):
    return (k*POW[k-1]+POW[k])%MOD

def func(left, right):
    return func2(left)*func2(right)%MOD

MOD = 998244353
POW = [1]
for _ in range(N):
    POW.append(POW[-1]*2%MOD)

ans = 0
for i in range(N):
    ans += A[i]*func(i, N-1-i)%MOD
    ans %= MOD

print(ans)