Questions tagged [palindrome]

A palindrome is a word, phrase, number, or other sequence of characters which reads the same backwards and forwards.

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6 votes
1 answer

Palindrome from the first 16 *roman* numbers

Can you concatenate the numbers from I to XVI in some order, such that the resulting 38-letter string is a palindrome? This puzzle was inspired by a recent puzzle by Dmitry Kamenetsky.
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0 votes
1 answer

Largest 5-digit palindrome in base 16, where each digit appears at most twice

What is the largest number $ x $ such that $ x_{16}, $ i.e. $ x $ in base 16, is a 5-digit long palindrome, where each digit appears at most twice? A palindrome is a number that reads the same forward ...
  • 111
-3 votes
1 answer

Add or subtract 212 in octal to get a palindrome

The puzzle is as follows: Suppose you have a three-digit number in the octal system. If you add or subtract 212 (also in the octal system) from that initial number, you get a three-digit palindromic ...
2 votes
2 answers

Smallest four-digit palindromic numbers

What is the smallest four-digit palindrome that is the sum of two different three-digit palindromic numbers? There are different answers.
  • 455
3 votes
1 answer

A lad named E. Mandala

In a follow up from yesterday, I was sent another email from the same source. The tile of the message was, "A lad named E. Mandala" which I've set the title of this puzzle to. Can you help ...
  • 9,547
3 votes
1 answer

Determine all possible positive palindrome(s) numbers [closed]

Determine all possible positive palindrome(s) N numbers, such that the decimal representation of 2 x N^2 has no leading zeroes and contains each of the digits from 0 to 9 exactly once.
  • 4,452
2 votes
3 answers

Multiply 2 palindromic alphametics to make a pandigital number

There are some different definitions of pandigital numbers, so to avoid misinterpretation, lets use this definition: Pandigital numbers (pandigit) are numbers containing the digits 0-9, where each ...
8 votes
1 answer

Palindrome in a cesarian code

Here's some album art from my favorite album "Trinity" by "Sons of Perdition": I've learned from reliable sources that the coordinates on this map are actually a cesarean cipher with a shift of , ...
  • 183
17 votes
1 answer

The same forwards and backwards, What am I?

Read forwards or backwards I'm the same Remove my last two letters I sound like a single letter Without my first two letters I'm trivial and sound like I'm an animal Leave only my second and fourth ...
  • 4,105
0 votes
1 answer

Longest Palindrome [closed]

What is the longest palindrome created? For those who don't know A palindrome is a word or series of words that read the same forwards as backwards. For example: hannah A man a plan a canal Panama ...
5 votes
1 answer

Recreating palindromes

In this puzzle, I am offering you the paraphases of English palindromic phrases. That is, I take a phrase: replace each fragment of the phrase with synonymous expressions: My god, a low voice is ...
  • 745
2 votes
2 answers

What is the largest 12 digit palindrome number divisible by 7?

A palindrome number is a number that is the same forwards as backwards. Some examples are 3443, 12321, and 59095. Here's my question: What is the largest 12 digit palindrome that is evenly divisible ...
  • 318
4 votes
1 answer

The Palindrome Grid

There is a 7-by-7 square grid containing an "A" and "B" in each square, in a checkerboard pattern. You must get the board to have no palindromes in it, going horizontally or vertically, in a full row ...
  • 1,254
48 votes
2 answers

Where did Billy go to?

There are lots of happy animals living with me in my house. Yesterday I wanted to enjoy an animal-free afternoon: I looked at Skippy and said "Go to festival". And off he hopped. Then I sent Cookie ...
  • 11.6k
13 votes
3 answers

Who wins the AI-game?

Anna and Isadora play a game by writing letters on the blackboard. In the first round, Anna starts by writing down the letter $A$ or the letter $I$. In the $n$-th round with $2\le n\le 999$, Anna ...
  • 45k