my @new_sn = get_new_numbers(1000, "10011902APWPA");

foreach(@new_sn){
  print $_."\n";
}

# A = 65 - Z = 90
sub get_new_numbers{
  my $anzahl = shift;
  my $last_sn = shift;
  my @back_array;
  
  #print $last_sn."\n";
  my ($mat, $last5);
  
  if( $last_sn =~ /(\w*)(\w{5})/ )  { $mat = $1; $last5 = $2; }
  
  my @c = split(//,$last5);
  foreach(@c){ $_ = ord($_); }
  
  foreach(1..$anzahl){
    @c = reverse(@c); 
    my $help_var = 0;
    foreach(@c){     
      ($help_var, $_) = count($_);
      last unless $help_var;
    }
    
    @c = reverse(@c);
    my $new_sn = $mat;
    foreach(@c){
     $new_sn .= chr($_);
    }
    push(@back_array, $new_sn);
  }
  
  return @back_array;
}

sub count{
  my $c_dec = shift;
  
  if( ++$c_dec > 90 ){
    $c_dec = 65; 
    return (1, $c_dec);
  }
  return (0, $c_dec);
}