/* 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[]
}