code: function encodeFor(n) {
    return (
        n === 1 ? encode
      : n === 2 ? encode2
      : n === 3 ? encode3
      : n === 4 ? encode4
      : encode5
    )
  }
docs: Get an encode function to encode an `n * 6` bit number
  
  @name encodeFor
  
  @param {Number} n number of 6 bits to encode
  @returns {function} the matching encoding function