题解 | #等差数列#
等差数列
https://www.nowcoder.com/practice/f792cb014ed0474fb8f53389e7d9c07f
#include<stdio.h>
int main()
{
int n = 0;
scanf("%d", &n);
int arr[1000] = { 2 };
int m = 0;
for (int i = 0; i < n; i++)
{
arr[i + 1] = arr[i] + 3;
}
for (int i = n; i > 0; i--)
{
m += arr[n-i];
}
printf("%d", m);
return 0;
}