n = int(input())
*a, = map(int,input().split())
MOD = 998244353
p2 = [1]
for i in range(n+3): p2.append(p2[-1]*2%MOD)
ans = 0
for i,ai in enumerate(a):
    v = p2[i] + i*p2[i-1]
    ans += v%MOD*p2[n-i-1]%MOD*ai%MOD
print(ans%MOD)