Random numbers 1-13 that don't repeat more than once

[GoToLoop]

final IntList sequence = IntList.fromRange(1, 14);
println(sequence);//IntList size=13 [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 ]

sequence.shuffle(this);
println(sequence);

exit();