From Wikipedia, the free encyclopedia:

 A happy number is defined by the following process:
 Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals   1   (where it will stay),   or it loops endlessly in a cycle which does not include   1.   


 Those numbers for which this process end in   1   are       happy   numbers,   
 while   those numbers   that   do   not   end in   1   are   unhappy   numbers. 


Task

Find and print the first   8   happy numbers.

Display an example of your output here on this page.



See also

   The OEIS entry:   The     happy numbers:   A007770
   The OEIS entry:   The unhappy numbers;   A031177


// version 1.0.5-2
 
fun isHappy(n: Int): Boolean {
    val cache = mutableListOf<Int>()
    var sum = 0
    var nn = n
    var digit: Int
    while (nn != 1) {
        if (nn in cache) return false
        cache.add(nn)
        while (nn != 0) {
            digit = nn % 10
            sum += digit * digit
            nn /= 10
        }
        nn = sum
        sum = 0
    }
    return true 
}
 
fun main(args: Array<String>) {
    var num = 1
    val happyNums = mutableListOf<Int>()
    while (happyNums.size < 8) {
        if (isHappy(num)) happyNums.add(num)
        num++
    }
    println("First 8 happy numbers : " + happyNums.joinToString(", "))
}