The number 666 is considered to be the occult "number of the beast" and is a well-used number in all major apocalypse themed blockbuster movies. However the number 666 can't always be used in the script so numbers such as 1666 are used instead. Let us call the numbers containing at least three contiguous sixes beastly numbers. The first few beastly numbers are 666, 1666, 2666, 3666, 4666, 5666...
Given a 1-based index n, your program should return the n-th beastly number. Your program should loop as long as the user wishes to.
- n will be between 1 and 10000, inclusive