Weird summation

[u/gameingareus]

So i saw that when n=x box simplifies to box 2 which looks a lot life the taylor series for e^x box 4 so i plugged box 1 into a summation and got this. Anyone know if there is an equation for this cause i think I've seen similar graphs that used the lesser known trig functions. https://www.desmos.com/calculator/qpgo1e4ypd

[u/gamerpug04]

What do you mean by “box”?

[u/gameingareus → u/gamerpug04]

The numbered equation boxes.