题解 | #等差数列#
等差数列
https://www.nowcoder.com/practice/f792cb014ed0474fb8f53389e7d9c07f
#include <iostream> using namespace std; int main() { int n; cin >> n; int a=0; int a0 =2; for(int i=0;i<n;i++){ a = a + a0; a0 = a0 + 3; } cout << a << endl; } // 64 位输出请用 printf("%lld")