use List::Util qw(first);

my @primes = (2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47);

sub listprimes {
    my $n = shift;
    my @foo;
    first { !($_ < $n ? push @foo, $_ : 0) } @primes;
    @foo;
    }

sub random {
    my ($lo, $hi) = @_;
    return $lo + int rand $hi - $lo + 1;
    }

for (1 .. 5) {
    my $r = random (10, 50);
    my @f = listprimes ($r);
    say "r == $r:  @f";
    }