poj--3086

escription

The n^th Triangular number, T(n) = 1 +
… + n, is the
sum of the first n integers.
It is the number of points in a triangular array with n points on side. For
example T(4):

X X X X X X X X X X

Write a program to compute the weighted sum of triangular numbers:

W(n) = SUM[k = 1…n; k * T(k +
1)]

Input

The first line of input contains a single integer N,
(1 ≤ N ≤ 1000) which is the number of
datasets that follow.

Each dataset consists of a single line of input containing a single
integer n, (1
≤ n ≤300), which is the number of points
on a side of the triangle.

Output

For each dataset, output on a single line the dataset number (1 through N), a
blank, the value of n for the dataset, a blank, and the
weighted sum ,W(n), of triangular numbers
for n.

Sample Input

4

3

4

5

10

Sample Output

1 3 45

2 4 105

3 5 210

4 10 2145

具体代码：

#include <iostream>

#include <cstdio>

#include <cstdlib>

#include <cstring>

using namespace std;

int main()

{

    int t, n;

    scanf("%d", &t);

    for (int i = 0; i < t; i++)

    {

        scanf("%d", &n);

        int w = 0, x = 1;

        for (int j = 1; j <= n; j++)

        {

            x += j + 1;

            w += j * x;

        }

        printf("%d %d %d\n", i + 1, n, w);

    }

    return 0;

}

poj--3086