尼科彻斯定理
public static void main(String[] args) {
long m = 6;
long a = m * m - m + 1;
System.out.println(a);
for (int i = 1; i < m; i++) {
System.out.print("+" + (a += 2));
}
}
原文：https://www.cnblogs.com/dongma/p/13224060.html