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## My favourite palindromes

I love palindromes, I think there must be something about a love of mathematics, because palindromes are symmetric. As much as I love them, I am equally bad at remembering them.

Here are a few that I either knew or were suggested on FaceBook a few days ago.

• “A man, a plan, a canal, Panama”
• “Do geese see God?”
• “Mum” (thank you Malcolm Bradley for this one)
• “Madam, I’m Adam” (thanks to Mike Merrifield for reminding me of this one)
• “Rise to vote sir” (thanks to Josh Davies for this one)
• “doc, note. I dissent. A fast never prevents a fatness. I diet on cod” (thank you to David Darling for this one)

Do you have any favourites? Add them into the comments section below.

### 25 Responses

1. Palindromes always inspire wonderment in me at the clever use of letters.
Relish these….
As I pee, sir, I see Pisa.
A Santa at Nasa.
rotator
Too hot to hoot.

• Those are some good ones. Thank you!

2. What is the one English palindromic compound word?

• Um, let me think.

• OK.

.

• Racecar.

• hehe. Good. What about a German palindrome that non-German speakers could appreciate? π

• German isn’t especially rich in palindromes. There are, however, a fair number of palindromic names (some of which exist in other languages): Otto, Onno, Ada, Anna. Not Eve, though, who is Eva in German.

• Eve is Efa in Welsh. Or, we should say that Eva/Efa is Eve in English π

3. Some people have written entire books which are palindromes.

• Yes but they’re just stringing words together. David Darling’s is about the longest I’ve seen that makes sense.

I prefer pi

• I don’t see how 3.14159… is a palindrome π

• Here is a serious mathematical question: Is there a digit x such that the first x digits of pi are palindromic? If one can’t name such a number, can one prove that it exists? That it doesn’t exist?

On the other hand, e is a trivial palindrome. π

• Hm, my understanding of a transcendental number such as pi is that a transcendental number is infinite and never repeats. That is one of the things that makes it different from an irrational number. And this can be rigorously proven, although how I don’t know as I am not a good enough mathematician.

There are of course some digits in pi where you get a palindrome, so e.g. if you have 3.14159…. then obviously the “141” is a numeric palindrome, but only 3 digits long. But what is the most number of digits in pi which exhibit a numeric palindrome is very interesting. 5? 7? 9? More? I have no idea!

• This also reminds me of Sheldon’s famous question in The Big Bang Theory – “What is the best number? There’s only one answer.”

“The best number is 73. Why? 73 is the 21st prime number. Its mirror (37) is the 12th and its mirror (21) is the product of multiplying 7 and 3. … In binary, 73 is a palindrome, 1001001 which backwards is 1001001.”

• If an irrational or transcendental number are both composed of an infinite series of non repeating numbers then surely there is an infinitely long numerical palindrome somewhere in that infinite series? Being infinite it contains all possibilities.

• Irrational numbers don’t repeat; rational numbers do (perhaps the repetition is 000… which is usually not indicated). So, 0.75, or 0.75000… is rational, but so is 1/7, which is 0.142857142857…. A transcendental number, on the other hand, is a number which is not a root of a non-zero polynomial equation with rational coefficients. So, all transcendental numbers are irrational, but not all irrational numbers are transcendental.

Your second paragraph is more what I meant. Yes, 141 is a palindrome, but this doesn’t work if one includes the 3 before the decimal point. Theoretically, I see no reason why the first x digits, for some very large x, could not be repeated in reverse order (or repeated a finite number of times in the same order), but of course one would never have perpetual repetition.

• As I say, I am not a mathematician. Yes, after checking, you are right an irrational number does not repeat either.

5. on 23/07/2013 at 15:58 | Reply Bill Mechior

One of the standards:

Able was I ere I saw Elba.

• There is a place in South Australia called “Glenelg”

6. Go hang a salami, I’m a lasagna hog (http://www.youtube.com/watch?v=JUQDzj6R3p4)

7. on 24/07/2013 at 00:32 | Reply Ana Maria

It’s short, but it’s me.
Ana

8. Continuing Phillip’s theme of Eva being German for Eve,and therefore not a palindrome, in Welsh the name for Adam is a palindrome, “Adda”……