Riemann Zeta Key Lime Pie

I asked my nerd friend what pi-related thing I should make into a pie form.
The answer I got:
"You should use the Riemann zeta function with power 2. i.e. 1/1 + 1/4 + 1/9 + 1/16 + ... + 1/n^2 + ... = (pi^2)/6."

I was totally lost at this, but made a polar plot of the function for him.

Key Lime
Single all butter pie crust with almonds , blind baked
 (use leftover dough to make graph axes)
1/2 cup freshly squeezed Key lime juice
1 teaspoon Key lime zest
3 large eggs, 2 eggs separated
1 14-oz can of sweetened condensed milk

1/2 cup whipping cream
1 tablespoon powdered sugar
green food coloring

Preheat the oven to 325F.
Mix 2 egg yolks and 1 egg with the lime juice, zest and condensed milk. set aside.
Add a couple of drops of key lime juice to the egg whites and whip until the meringue forms still peaks.
Fold in the egg whites into the yolk mixture, pour into the crust and bake at 325F for 15 min or until set.
Chill completely in the refrigerator.

Meanwhile, whip heavy cream with sugar and food coloring for decoration.
Once the pie is cold, pipe the heavy cream to draw Riemann Zeta function on the pie.