Attempt Number: 4
Error Message: The action and resulting child state have already been explored.

Action Reasoning:
Robot1 is currently at tile_1-4, holding a white paint gun. The goal is to paint the tiles in row 0 in an alternating color pattern starting with black. Since the last action was a move, the next step should be to change the color of the paint gun to black, which is the target color for tile_0-0. This will prepare Robot1 to paint the first tile in the goal sequence.

New State Description:
Robot1 is still at tile_1-4, but now it is holding a black paint gun.

Action Chosen:
change-color(robot1, white, black)
