(50g) OEIS A028842: Product of Digits is a Prime

[Gerald H]

For integer input N the programme returns the Nth element of the series

https://oeis.org/A028842

where the elements are all numbers in naturally ascending order whose product of digits is a prime.

I am particularly unhappy with this

4. OVER
WHILE DUP2 <
REPEAT OVER -
SWAP 4. + SWAP
END

section of code & would welcome a speedier method of calculating the 2 numbers deposited on the stack.

SIZE 173.

CKSUM # 502Fh

Code:

« 4. OVER
  WHILE DUP2 <
  REPEAT OVER -
SWAP 4. + SWAP
  END "" 1. 4. ROLL
4. /
  START "1" +
  NEXT OBJ→ SWAP 4.
IDIV2 DUP
  IF
  THEN DUP 3. ==
    IF
    THEN DROP 4
    END
  ELSE DROP 1. - 6
  END 10 ROT R→I ^
* + SWAP DROP
»