#include <iostream>
#include <cstdint>
#include <vector>
#include <algorithm>

using namespace std;

static inline constexpr uint64_t solve(const uint32_t N, const vector<uint32_t>& A)
{
	uint64_t ans = 0;
	for (uint32_t i = 0, j = 1, k = 1; i != N; i = j, ++j)
	{
		while (A[i] == A[j]) ++j;
		while (A[i] * 2 > A[k]) ++k;
		ans += static_cast<uint64_t>(j - i) * (j - i - 1) / 2 * (k - (j - i));
	}

	return ans;
}

int main()
{
	cin.tie(nullptr);
	ios::sync_with_stdio(false);
	
	uint32_t N, i;
	cin >> N;
	vector<uint32_t> A(N + 1);
	for (i = 0; i != N; ++i)
		cin >> A[i];
	A[N] = UINT32_MAX;

	sort(A.begin(), A.end());
	cout << solve(N, A) << '\n';
	return 0;
}