Buggy python submission (verdict: Runtime Error):
import sys
import itertools
input = sys.stdin.readline
sys.setrecursionlimit(100000)
mod = 10 ** 9 + 7

def read_values(): return map(int, input().split())
def read_index(): return map(lambda x: int(x) - 1, input().split())
def read_list(): return list(read_values())
def read_lists(N): return [read_list() for n in range(N)]


class V:
    def __init__(self, f):
        self.f = f
        self.v = None
 
    def __str__(self):
        return str(self.v)
 
    def ud(self, n):
        if self.v is None:
            self.v = n
        else:
            self.v = self.f(self.v, n) 


def f(N, S, A, L, R, exist=False):
    if S == 0:
        return [[0, L - 1]]

    SS = sum(A[L:R + 1])
    if SS < S:
        return []
    if SS == S:
        return [[L, R]]
    if L == R:
        return []

    T1 = f(N, S, A, L + 1, R, exist)
    T2 = f(N, S - A[L], A, L + 1, R, True)

    if not exist and len(T2) > 0:
        for l in T2:
            l[0] = L
    T1.extend(T2)
    return T1


def main():
    N = int(input())
    S = read_list()

    dp = [[0 for _ in range((N + 1) // (c + 1) + 1)] for c in range(N)]
    res = V(max)
    res.ud(0)
    for c in range(1, N):
        T = set()
        for k in range(1, N):
            t1 = k * c
            t2 = (N - 1) - t1 
            if t1 >= N - 1:
                break
            
            if t1 == t2:
                break

            if t1 in T or t2 in T: 
                break
            dp[c][k] = dp[c][k - 1] + S[t1] + S[t2]
            T.add(t1)
            T.add(t2)
            res.ud(dp[c][k])

    print(res)


if __name__ == "__main__":
    main()


Fixed submission:
import sys
import itertools
input = sys.stdin.readline
sys.setrecursionlimit(100000)
mod = 10 ** 9 + 7

def read_values(): return map(int, input().split())
def read_index(): return map(lambda x: int(x) - 1, input().split())
def read_list(): return list(read_values())
def read_lists(N): return [read_list() for n in range(N)]


class V:
    def __init__(self, f, v=None):
        self.f = f
        self.v = v
 
    def __str__(self):
        return str(self.v)
 
    def ud(self, n):
        if self.v is None:
            self.v = n
        else:
            self.v = self.f(self.v, n) 


def main():
    N = int(input())
    S = read_list()

    res = V(max, 0)
    for c in range(1, N):
        r = 0
        t1 = 0
        t2 = N - 1
        a = t2 - c
        while True:
            if a < c:
                break
            
            if (N - 1) % c == 0 and 2 * a <= N - 1:
                break

            t1 += c
            t2 -= c
            a -= c
            r += S[t1] + S[t2]
            res.ud(r)

    print(res)


if __name__ == "__main__":
    main()

Buggy python submission (verdict: Runtime Error):
import sys
import itertools
input = sys.stdin.readline
sys.setrecursionlimit(100000)
# mod = 10 ** 9 + 7
mod = 998244353

def read_values(): return map(int, input().split())
def read_index(): return map(lambda x: int(x) - 1, input().split())
def read_list(): return list(read_values())
def read_lists(N): return [read_list() for n in range(N)]


class V:
    def __init__(self, f):
        self.f = f
        self.v = None
 
    def __str__(self):
        return str(self.v)
 
    def ud(self, n):
        if self.v is None:
            self.v = n
        else:
            self.v = self.f(self.v, n) 


def f(N, S, A, L, R, exist=False):
    if S == 0:
        return [[0, L - 1]]

    SS = sum(A[L:R + 1])
    if SS < S:
        return []
    if SS == S:
        return [[L, R]]
    if L == R:
        return []

    T1 = f(N, S, A, L + 1, R, exist)
    T2 = f(N, S - A[L], A, L + 1, R, True)

    if not exist and len(T2) > 0:
        for l in T2:
            l[0] = L
    T1.extend(T2)
    return T1


def main():
    N = int(input())
    S = read_list()

    dp = [[0 for _ in range(N)] for __ in range(N)]
    res = V(max)
    res.ud(0)
    for c in range(1, N):
        T = set()
        for k in range(N):
            t1 = (k + 1) * c
            t2 = (N - 1) - t1 
            if t1 >= N - 1:
                break
            
            if t1 == t2:
                break

            if t1 in T or t2 in T: 
                break
        
            dp[c][k + 1] = dp[c][k] + S[t1] + S[t2]
            T.add(t1)
            T.add(t2)
            res.ud(dp[c][k + 1])

    print(res)



if __name__ == "__main__":
    main(

Fixed submission:
import sys
import itertools
input = sys.stdin.readline
sys.setrecursionlimit(100000)
mod = 10 ** 9 + 7

def read_values(): return map(int, input().split())
def read_index(): return map(lambda x: int(x) - 1, input().split())
def read_list(): return list(read_values())
def read_lists(N): return [read_list() for n in range(N)]


class V:
    def __init__(self, f, v=None):
        self.f = f
        self.v = v
 
    def __str__(self):
        return str(self.v)
 
    def ud(self, n):
        if self.v is None:
            self.v = n
        else:
            self.v = self.f(self.v, n) 


def main():
    N = int(input())
    S = read_list()

    res = V(max, 0)
    for c in range(1, N):
        r = 0
        t1 = 0
        t2 = N - 1
        a = t2 - c
        while True:
            if a < c:
                break
            
            if (N - 1) % c == 0 and 2 * a <= N - 1:
                break

            t1 += c
            t2 -= c
            a -= c
            r += S[t1] + S[t2]
            res.ud(r)

    print(res)


if __name__ == "__main__":
    main()