The code ‘A113’ appears in almost every movie made by Pixar, and quite a few Disney movies, too. The code signifies the number of the animation classroom at the California Institute of the Arts where many of the Pixar and Disney animators studied.
It was a first year graphic design and character animation classroom, and by adding the code in every movie they politely honor the once-shared classroom.
The code appears in many movies. Take a look.