- #1

- 15

- 1

2,3,5,7 and 23, 23 being the first double digit prime whose digits are all prime.

- Thread starter fibonacci235
- Start date

- #1

- 15

- 1

2,3,5,7 and 23, 23 being the first double digit prime whose digits are all prime.

- #2

arildno

Science Advisor

Homework Helper

Gold Member

Dearly Missed

- 9,970

- 132

Reason?

It ought to be just an artefact of the particular number representation system you use.

If you let "11" be your base number, rather than 10, your "23" will be written as 21, the latter digit not being prime at all.

The quality of a number being prime is independent of its particular representation, but you cant expext the same for the digits of two distinct representations of the same number.

- #3

- 15

- 1

- #4

arildno

Science Advisor

Homework Helper

Gold Member

Dearly Missed

- 9,970

- 132

Sure, some of dubbed palindromic numbers as being palindromic. But, just because you set a name on something doesn't mean it constitutes anything worthwhile studying (i.e, nobody studies palindromic numbers)

The reason why palindromic numbers have gotten their name is that the property of palindromy is well known outside maths, so it sort of stuck.

I would be extremely surprised if anyone has given your types of perfectly definable numbers a particular name (I'm not at all saying your question was vague or anything. It wasn't, your first post was perfectly clear)

- #5

- 433

- 120

This sounds like "Happy numbers" which are also base dependent.

- #6

- 15

- 1

Then I think I will name them Digital Primes.

Sure, some of dubbed palindromic numbers as being palindromic. But, just because you set a name on something doesn't mean it constitutes anything worthwhile studying (i.e, nobody studies palindromic numbers)

The reason why palindromic numbers have gotten their name is that the property of palindromy is well known outside maths, so it sort of stuck.

I would be extremely surprised if anyone has given your types of perfectly definable numbers a particular name (I'm not at all saying your question was vague or anything. It wasn't, your first post was perfectly clear)

- Last Post

- Replies
- 12

- Views
- 3K

- Last Post

- Replies
- 1

- Views
- 2K

- Replies
- 10

- Views
- 18K

- Replies
- 3

- Views
- 2K

- Last Post

- Replies
- 1

- Views
- 634

- Last Post

- Replies
- 12

- Views
- 4K

- Last Post

- Replies
- 15

- Views
- 7K

- Last Post

- Replies
- 8

- Views
- 1K

- Last Post

- Replies
- 6

- Views
- 2K

- Last Post

- Replies
- 1

- Views
- 1K