MOD = 998244353

n = int(input())
a = list(map(int, input().split()))

if n < 3:
    exponent = (n - 3) % (MOD - 1)  # Fermat's little theorem
else:
    exponent = n - 3
pow_term = pow(2, exponent, MOD)

total = 0
for i in range(n):
    pos = i + 1  # 1-based index
    part_a = pos - 1
    part_b = n - pos
    coeff = (2 * (n + 1) + part_a * part_b) % MOD
    contrib = (pow_term * coeff) % MOD
    total = (total + a[i] * contrib) % MOD

print(total)