"In order to detect any malfunction in the calculator, design a logic circuit which will detect if the calculator has output in error any of the six 4-bit values that you have NOT used in your own personal unweighted BCD code. Obtain the circuit in its SIMPLEST form and give its Boolean equation and gate level circuit diagram."

I have the six 4-bit binary values and I have no idea how I can design this logic circuit , I was going to set each of their output to "1" indicating it's an error like:

A B C D F

0 0 0 0 1

0 1 0 0 1

1 0 0 0 1

1 1 0 0 1

1 1 1 1 1

And then do a K-map based on the above truth table but then I thought this is not making any sense at all, I think the solution must be very simple because they just started teaching these stuff in the Foundation course I'm studying. Could someone please give me a clue what I should do ? Thank you.