By creating a latex block in in markdown with $$ $$ I get a decent display of the formula with my local jupyter plugin (vesion 2025.4.1) in vs code.

I doublechecked this with the try section on jupyter.org which gave me the following output:

If don't need the \begin(align) ... \end(align) for a specific reason, try to use:

$$
F(t) = \frac{1} {4} \cdot \sum_{n=0}^{\infty} \frac{1} {(2\,n+1)!} \cdot t^n
$$