What resistor do I use for this circuit?

[Paul_B]

CrossRoads:
Or: use 2 5Ks in series, with junction to LCD pin indicated.

Eh? Did you not read the question?

This is the contrast control for the LCD.

As an approximation, you can use a 470 ohm resistor from V_o (pin 3) to ground and try a 10k resistor from V_o to V_cc which may be better or worse for the contrast.