use strict;
my @set_of_stuff = (1,3,4,6,7,8,10,12,13,14,15,19,23);
my $items_per_row = 4;
my @table_data;

for (0 .. scalar @set_of_stuff / $items_per_row) {
  my @row_data = map {$_={cell_data=>$_ }} splice(@set_of_stuff,0,$items_per_row);
  push @row_data, {cell_data=>'&nbsp'} while scalar @row_data < $items_per_row;
  push @table_data, { row_data => \@row_data };
}

##</code><code>##

use HTML::Template;
my $template = q{
<TABLE border=1><TMPL_LOOP name="table_data">
  <TR><TMPL_LOOP name="row_data">
    <TD><TMPL_VAR name="cell_data"></TD>
  </TMPL_LOOP></TR>
</TMPL_LOOP></TABLE>
};

my $template = HTML::Template->new(scalarref => \$template, option => 'value');
$template->param(table_data => \@table_data);
print $template->output();