import string
digs = string.digits + string.lowercase+string.uppercase

def int2base(x, base):
  if x < 0: sign = -1
  elif x==0: return '0'
  else: sign = 1
  x *= sign
  digits = []
  while x:
    digits.append(digs[x % base])
    x /= base
  if sign < 0:
    digits.append('-')
  digits.reverse()
  return ''.join(digits)

for b in range(3,50):
  print "Checking base : "+str(b)
  for i in range(4,100000):
    if(int2base(i,b)==int2base(2*i,b)[::-1]):
      print str(i)+'\t'+int2base(i,3)