Problem Statement

The Luhn test is used by some credit card companies to distinguish valid credit card numbers from what could be a random selection of digits. Those companies using credit card numbers that can be validated by the Luhn test have numbers that pass the following test:

For example, if the trial number is 49927398716:

Write a function/method/procedure/subroutine that will validate a number with the Luhn test, and use it to validate the following numbers:

Let's start with the solution:

v  1   >$0 v   v                                    <
>&:19+`|v  <            >v      5      6   7      8
^  \   <>09p19p>09g+09p:|>2*:19+%19g+19p19+/19g+19p:|
   2          3      4  >                           v
                              v"invalid"<10  9
                                        |%+91+g91g90<
                              v  "valid"<
                              >:#,_@
                                 11