题解 | #尼科彻斯定理#

const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;

void (async function () {
    // Write your code here
    while ((line = await readline())) {
        let m = parseInt(line);
        let res = [];
        let times;
        if (m == 1) {
            console.log(1);
            return;
        }
        //中间项是 m ^ 2
        let center = m * m;
        let flag = m % 2;
        if (flag) {
            times = (m - 1) / 2;
            // 当 m 是奇数时，中间项是其平方
            res.push(m * m);
        } else {
            times = m / 2;
        }

        for (let i = 1; i <= times; i++) {
            if (flag) {
                res.unshift(center - 2 * i);
                res.push(center + 2 * i);
            } else {
                res.unshift(center - (2 * i - 1));
                res.push(center + (2 * i - 1));
            }
        }

        console.log(res.join('+'));
    }
})();