数字黑洞，指的是某种运算，这种运算一般限定从某些整数出发，反复迭代后结果必然落入一个点或若干点。任意整数a，如果它的偶数位的个数为b，奇数位的个数为c，b和c的和为d，那么定义运算@：@a = bcd，比如 @647382 = 426。那么123数字黑洞可以描述为：对于任意整数a，有While（a != 123）a = @a 这个循环可以结束。比如整数274829，@274829 = 426，@426 = 303，@303 = 123，可见，274829经过三次变换变成了123，现在，给你一个整数a，你知道它要经过几次变换才能变成123吗？-Digital black hole, is referring to some kind of operation, this operation is generally limited to an integer starting from a certain, inevitable result after iteratively into a point or several points. An arbitrary integer a, even if it s the number of bits of b, the number of odd bits c, b and c and d, and then define the operator @: @ a = bcd, such as @ 647 382 = 426. Then 123 digital black hole can be described as: For any integer a, a While (a! = 123) a = @ a　this cycle can end. Such as integer 274 829 @ 274 829 = 426, @ 426 = 303, @ 303 = 123, shows that 274,829 after three transformations into a 123, now, to give you an integer a, you know it has to go through several transformations to become a 123 it?