#!/usr/bin/perl

use strict;
use warnings;

my $MAX = shift;

my $re = qr /^(1+)(??{"(?:$1){" . (length ($1) - 1) . "}" })$/;

for (1 .. $MAX)
    {printf "%3d is a square\n" => $_ if (1 x $_) =~ /$re/}
do  {printf "%3d is a square\n" => $_ if (1 x $_) =~ /$re/} for 1 .. $MAX;
map {printf "%3d is a square\n" => $_ if (1 x $_) =~ /$re/}     1 .. $MAX;

##</code><code>##

perl -le "print $_,system(qq{perl script.pl $_ > dump.out})?' NOK':' ok' for (1..275)"

##</code><code>##

perl -le'print $_,$",system("perl script.pl $_ > /dev/null")?"NOK":"ok" for (1..275)'