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binary = [ 2**x for x in range(20) ][::-1]
def palindromic_decimal(n):
if n == int(str(n)[::-1]):
return True
return False
def dec2bin(n):
res = ""
for i in binary:
if n - i > 0 or n == i:
res += "1"
n -= i
else:
if len(res) > 0: # do not add leading 0s
res += "0"
return res
def bin2dec(n):
res = 0
for i in range(1, len(n)+1):
if n[-i] == "1":
res += binary[-i]
return res
def palindromic_binary(n):
if n == bin2dec(dec2bin(n)[::-1]):
return True
return False
sum = 0
for n in xrange(1000000):
if palindromic_decimal(n) and palindromic_binary(n):
sum += n
print sum
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