Distinct power numbers

Distinct power numbers is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

Task

Let given all integer combinations of $a^{b}$ for $2<=a<=5$ and 2 <= b <= 5:

Place them in numerical order, with any repeats removed.

We get the following sequence of 15 distinct terms:
4, 8, 9, 16, 25, 27, 32, 64, 81, 125, 243, 256, 625, 1024, 3125

Ring

<lang ring> load "stdlib.ring"

see "working..." + nl see "Distinct powers are:" + nl row = 0 distPow = []

for n = 2 to 5

   for m = 2 to 5
       sum = pow(n,m)
       add(distPow,sum)
   next

next

distPow = sort(distPow)

for n = len(distPow) to 2 step -1

   if distPow[n] = distPow[n-1]
      del(distPow,n-1)
   ok

next

for n = 1 to len(distPow)

   row++
   see "" + distPow[n] + " "
   if row%5 = 0
      see nl
   ok

next

see "Found " + row + " numbers" + nl see "done..." + nl </lang>

Output:

working...
Distinct powers are:
4 8 9 16 25 
27 32 64 81 125 
243 256 625 1024 3125 
Found 15 numbers
done...