569,596,659,695,965,956

Allowing repetition is much more complicated. It is also very tiring to solve by power, because there are many repetitions of the same sign to be eliminated. Exhaustion is more appropriate here.

There are six non-duplicates, plus:

555

556

559

565

595

655

955

There are seven repetitions of the number 5, and the number 6 is the same as the number 9, so 7*3=2 1.

The allowed duplication is 6+2 1=27.