Creating an animation, after solving a Fourier Series.

I am attempting to solve multiple iterations of a Fourier series equation, store the outputs, and create an animation from the results. I've attached my current file. The problem I'm having at the moment is the appearance of matrices in my variables while trying to accumulate my results into output matrices. The error should appear when running. Hopefully this is only a few steps away from running correctly.

Any help is appreciated, thanks.

Sam