[Figuring out base 4] Python implementation

# v0.1: initial version. Only supported integers 0 - 1023
# v0.2: Added arg to function to support integers beyond 1023
# v0.3: Now it works with any integer that python can chew.
# v0.3.1: Bugfix. b10_4(1) would crash, so I added a special case for anything below 10 (decimal 4)
# v0.3.2: Bug affects any power of 4. So I changed the logic to fix that. < to <=
# v0.3.3: Added test() function and added default arg for b10_4()

def test(r=0x1000):
  for i in range(r):
    print("%X of %X:\t%s" % (i,r,b10_4(i)))

def b10_4(N=0):
  if N < 4: return str(N)
  n = 0
  i = 0
  outs = ""
  while 4**n <= N: n += 1
  out = [0 for j in range(n)]
  while n >= 0:
    while N >= 4**n:
      N -= 4**n
      out[n] += 1
    while N < 4**n:
      n -= 1
  out.reverse()
  while i < len(out):
    outs += str(out[i])
    i += 1
  return outs