is there a bug with zeta(n) ?

hello,

**Describe the bug**
when you use zeta(n) into math.evaluate(...)

**To Reproduce**
math.config({
number: "BigNumber",
precision: 998,
relTol: 1e-320,
absTol: 1e-323
});
math.evaluate("zeta(3)")
=> gamma.js:89 Uncaught Error: Integer BigNumber expected
at BigNumber (gamma.js:89:13)
at gamma (typed-function.js:1465:22)
at BigNumber (factorial.js:44:14)
at factorial (typed-function.js:1462:22)
at b (zeta.js:118:18)
at zeta.js:135:34
at x (zeta.js:98:14)
at y (zeta.js:64:12)
at BigNumber (zeta.js:36:23)
at zeta (typed-function.js:1465:22)