"Two Sets II" dynamic programming problem

I'm trying to solve https://cses.fi/problemset/result/3172518/#test11.

It states:

Your task is to count the number of ways numbers 1,2,…,n can be divided into two sets of equal sum.

For example, if n=7, there are four solutions:

{1,3,4,6} and {2,5,7}

{1,2,5,6} and {3,4,7}

{1,2,4,7} and {3,5,6}

{1,6,7} and {2,3,4,5}

This is what I got to now:

int n;
cin >> n;
int maxSum = n * (n + 1) / 2;
if (maxSum % 2 != 0) {
cout << 0 << endl;
return 0;
}
maxSum /= 2;
vector<vector<long>> dp(n+1, vector<long>(maxSum+1));
dp = 1;
for (int currentNumIncluded = 1; currentNumIncluded <= n; ++currentNumIncluded) {
for (int currentTargetSum = 0; currentTargetSum <= maxSum; ++currentTargetSum) {
dp[currentNumIncluded][currentTargetSum] = dp[currentNumIncluded-1][currentTargetSum];
int remainder = currentTargetSum - currentNumIncluded;
if (remainder >= 0) {
dp[currentNumIncluded][currentTargetSum] += dp[currentNumIncluded-1][remainder];
dp[currentNumIncluded][currentTargetSum] %= 1000000007;
}
}
}
cout << dp[n][maxSum]/2 << endl;

I use simple DP to solve it. However, it doesn't pass 5 out of 26 test cases. I looked it up and it turns out that if you print dp[n-1][maxSum] instead of dp[n][maxSum]/2 everything works. Could anyone explain this to me?