Calculate the Riemann Zeta Function Calculate the Riemann zeta function to the maximum primitive precision in your language (for C-family, that would be double or long double, var in JS, etc.) No need for BigDecimal or the like unless you need it to use a double-equivalent precision.


Efficiency (be sane) doesn't matter.
If it's not in a common language, I can't test it, but I hope somebody does.
No libraries or built-in math functions.
Recursion is cool!


See my JS entry for a sample program.
JavaScript (Chrome): 78
function zeta(r){for(var t=0,a=1,n=1;t!=a;a=t,t+=1/Math.pow(n++,r));return t}