from collections import Counter, deque, defaultdict
from heapq import heapify, heappop, heappush, nlargest, nsmallest
from bisect import bisect_left, bisect, bisect_right
from copy import deepcopy
from time import perf_counter
import sys
from typing import Any, List, Callable


def debug(*args, sep=" ", end="\n") -> None:
    print(*args, sep=sep, end=end, file=sys.stderr)


def main():
    global inf, MOD
    input = sys.stdin.read().split()
    ptr = 0
    inf = float("inf")
    MOD = 998244353

    N = int(input[ptr]); ptr += 1
    A = list(map(int, input[ptr:ptr + N])); ptr += N
    p = pow(2, N - 3, mod=MOD)
    debug(p)
    ans=0
    for i,a in enumerate(A):
        j=N-i-1
        k=p
        k*=i+2;k%=MOD
        k*=j+2;k%=MOD
        ans+=k*a;ans%=MOD
    print(ans)


if __name__ == "__main__":
    main()