O'Halloran numbers
my @Area;
my $threshold = 1000; # a little overboard to make sure we get them all
for 1..$threshold -> $x {
for 1..$x -> $y {
last if $x × $y > $threshold;
for 1..$y -> $z {
push @Area[my $area = ($x × $y + $y × $z + $z × $x) × 2], "$x,$y,$z";
last if $area > $threshold;
}
}
}
say "Even integer surface areas NOT achievable by any regular, integer dimensioned cuboid:\n" ~
@Area[^$threshold].kv.grep( { $^key > 6 and $key %% 2 and !$^value } )»[0];
Output:
Even integer surface areas NOT achievable by any regular, integer dimensioned cuboid:
8 12 20 36 44 60 84 116 140 156 204 260 380 420 660 924
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