from math import factorial
n=int(input())
a=list(map(int,input().split()))
point=0

def cmb(n, r):
    if n - r < r: r = n - r
    if r == 0: return 1
    if r == 1: return n

    numerator = [n - r + k + 1 for k in range(r)]
    denominator = [k + 1 for k in range(r)]

    for p in range(2,r+1):
        pivot = denominator[p - 1]
        if pivot > 1:
            offset = (n - r) % p
            for k in range(p-1,r,p):
                numerator[k - offset] /= pivot
                denominator[k] /= pivot

    result = 1
    for k in range(r):
        if numerator[k] > 1:
            result *= int(numerator[k])

    return result

def cm(l,i,j):
    a = cmb(i,j-1)
    b = 2**(len(l)-i-1)
    return int(a*b)

for i in range(n):
    for j in range(1,i+2):
        point+=a[i]*j*cm(a,i,j)
print(point%998244353)