题解 | #等差数列#
等差数列
http://www.nowcoder.com/practice/f792cb014ed0474fb8f53389e7d9c07f
我竟然还搞了个递归，一个个算出来。。。
let n = +readline();
let result = 0;
function sum(m) {
if(m == 1) {
return 2;
}
return sum(m-1) + 3;
}
for(let i = 1; i <= n; i++) {
result += sum(i);
}
console.log(result);
