pseudocodeBinSearch.js

//numPrimes is above in scope, array that maps bin to the number of primes up to it 
//takes n of the prime that we are looking for
//returns bin
function binSearch(target, bins){
  lastBin = bins[bins.size-1];
  if(target < numPrimes[lastBin] && target > numPrimes[lastBin-1]){
    return lastBin;
  }
  else if(target < numPrimes[lastBin]){
    return binSearch(target,bins.slice(0,bins.size/2));
  }
  else{
    return binSearch(target,bins.slice(bins.size/2+1,bins.size));
  }
}