Audioactive Sequence (idea)

This handy, little Perl script will display the audioactive sequence in the user-specified non-zero base. It should be noted that this sequence grows exponentially for all bases greater than 1. In base 1, however, the sequence grows linearly. Try AUDIOACTIVE.PL 1 10 and see for yourself (or just look at the short example runs below).

#!/usr/bin/perl
use strict;

# AUDIOACTIVE.PL
# This script takes 2 command line arguments: base and iterations
# If the base is not 1, 2, or 3 it is assumed to be 4
# because after 3, the sequence is the same regardless of base.

# Example: perl AUDIOACTIVE.PL 2 10

if($#ARGV != 1) {
  print STDERR "Usage: perl AUDIOACTIVE.PL <base> <iterations>\n";
  exit;
}

my ($str, $base, $max) = ('1', shift, shift);
my %hDecToBin  = qw(1 1 2 10 3 11 4 100);
my %hDecToTri  = qw(1 1 2  2 3 10 4  11);
my %hDecToQua  = qw(1 1 2  2 3  3 4  10);
my $hDecToBase = undef;

if($base < 1) {
  print STDERR "Base must be greater than 0, exiting program...\n";
  exit;
} elsif($base == 1) {
  print '1' x $_, "1\n" for (0..$max-1);
  exit;
} elsif($base == 2) {
  $hDecToBase = \%hDecToBin;
} elsif($base == 3) {
  $hDecToBase = \%hDecToTri;
} else {
  $hDecToBase = \%hDecToQua;
}

print "$str\n";
for(my $i=0; $i < $max-1; $i++) {
  my @str = split('', $str);
  $str = '';
  my ($num, $count) = ($str[0], 0);
  foreach (@str) {
    if($_ == $num) {
      $count++;
    } else {
      $str  .= $hDecToBase->{$count};
      $str  .= $num;
      $num   = $_;
      $count = 1;
    }
  }
  $str .= $hDecToBase->{$count};
  $str .= $num;
  print "$str\n";
}

Examples:
perl AUDIOACTIVE.PL 1 6
1
11
111
1111
11111
111111

perl AUDIOACTIVE.PL 2 6
1
11
101
111011
11110101
100110111011

perl AUDIOACTIVE.PL 3 6
1
11
21
1211
111221
1012211

perl AUDIOACTIVE.PL 4 6
1
11
21
1211
111221
312211

perl AUDIOACTIVE.PL 5 6
1
11
21
1211
111221
312211