Counting Triangles

描述

Given an equilateral triangle with n the length of its side, program to count how many triangles in it.

输入

The length n (n <= 500) of the equilateral triangle's side, one per line.
process to the end of the file

输出

The number of triangles in the equilateral triangle, one per line.

样例输入

1
2
3

样例输出

1
5
13

#include<iostream>using namespace std;int main(){int triangle[502]={0,1},i;for(i=2;i<=500;i+=2){triangle[i]=triangle[i-1]+i*(i+1)/2+i/2+(i/2)*(i/2-1);triangle[i+1]=triangle[i]+(i+1)*(i+2)/2+(i/2)*(i/2+1);}while(scanf("%d",&i)==1)cout<<triangle[i]<<endl;return 0;}