brander-edu1.coffee

memoize = (func, hashFunc) ->
  memo = {}
  hashFunc = hashFunc or (n) -> n
  () ->
    key = hashFunc.apply @, arguments
    if memo[key]? then memo[key] else memo[key] = func.apply @, arguments

fibonacci = memoize (n) ->
  if n < 2 then n else fibonacci(n - 1) + fibonacci(n - 2)

n = 2
[..., last] = while Math.abs(fibonacci(n) / fibonacci(n - 1) - fibonacci(n - 1) / fibonacci(n - 2)) > 10**-10
 n++
 fibonacci(n) / fibonacci(n - 1)

console.log n, last