I'm trying to get a specific converging series function worked out in JavaScript:

function cnvg(sum,marker){
  if((marker--||1000)>=0){
    return cnvg(sum=(sum||0) + 1/Math.pow(-3,marker)/(2*marker+1), marker)
  } else {
    return sum;
  }
}

I'm expecting cnvg() to come back with the equivalent of Math.PI/Math.sqrt(12) but I keep getting a "Maximum call stack size exceeded" error. I thought it may be the number of iterations, so I dropped the 1000 reference to 100 then 10 and finally to 1, but I still seem to be receiving the error.

Theoretically, once marker has counted down to 0 and executes the last loop it should stop and return the value of sum, but this doesn't seem to be the case... Can anyone tell me what I'm doing wrong?

Thanks in advance.

marker-- || 1000 will evaluate to 1000 when marker is 1 or 0, resulting in an infinite recursion. Did you mean:

function cnvg(sum, marker) {
  marker = (typeof(marker) === 'undefined') ? 1000 : marker--;
  if (marker >= 0) {
    return cnvg(sum=(sum||0) + 1/Math.pow(-3,marker)/(2*marker+1), marker)
  } else {
    return sum;
  }
}