How do you score and grounder too pitcher who throws to 1B for the out?

To score a grounder to the pitcher who throws to first base for the out, you record it as a ground ball out. The official scoring would be noted as a 1-3 putout, indicating the pitcher (1) fielded the ball and threw it to the first baseman (3) for the out. If the play was routine, you might simply note it as a groundout without any additional commentary.