N = int(input())
A = list(map(int, input().split()))
mod = 998244353
two = [1] * N
for i in range(2, N):
    two[i] = two[i-1]*2
    two[i] %= mod
    
two.reverse()
ans = two[0] * A[0]
for i in range(1,N):
    ans += two[i] * A[i] * (i + 2) * pow(2, i-1, mod)
    ans %= mod
    
print(ans)