/* A sequence of natural numbers is determined by the following formula,
A[n+1] = a[n] + f(n) Where f(n) is the product of digits in a[n]. Is
there an a[1] such that the above sequence is unbounded? */

for n = 175 million to billion
{
   a = n
   smallest = a
   do
   {
      lasta = a
      a = a + product[integerDigits[a]]
      print["$a "]
   } while a > smallest and a > lasta
   println[]
}