Another approach might be to read in all the used numbers before selecting a new one. You would need to optimize things here, but create a list of unused nums from your list of used nums, then randomly select a num from the unused list: 
use warnings;
use strict;
use Acme::Tools qw(minus);
use List::Util  qw(shuffle);

my @alls    = 0 .. 9;
my @useds   = qw(1 2 5 8); # from your aj.db
my @unuseds = shuffle(minus(\@alls, \@useds));
my $new_num = $unuseds[0];

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In reply to Re: Testing numeric strings by toolic
in thread Testing numeric strings by jlwoodruff

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