### PWC 177

PWC 177 Challenge 1 (Damm Algorithm) This challenge requires implementing the Damm algorithm which uses an extra check digit to catch errors in entering digits in a numeric code, especially the common transposition errors. In terms of programming, this is a simple matter of setting up a lookup table and then looking it up. I implement two subroutines, closely following the howto in the wikipedia page. "get_check_digit" calculates a check digit for a given number, and "validate" checks if a number is correct based on the extended number including a check digit. In Perl 5 and Raku, I indulge my atavistic leanings by setting up the lookup table as a flat list of strings. In Julia, it is easy to implement it as a matrix. This algorithm is useful enough to have its own CPAN module: Algorithm::Damm Here is my Perl 5 script. Here is my Raku script. Here is my Julia script. Challenge 2 (Palindromic Prime Cyclops) This challenge requires looking for the first 20 positive in