All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars
 perplexus dot info

 Does it continue? 3: Growing table of primes (Posted on 2017-09-19)
Before trying the problem "note your opinion as to whether the observed pattern is known to continue, known not to continue, or not known at all."

After row 1, row n is obtained by inserting n between every pair of consecutive numbers that sum to n.

```row 1:                  1 1
row 2:                 1 2 1
row 3:               1 3 2 3 1
row 4:            1 4 3  2  3 4 1
row 5:        1 5 4  3 5 2 5 3 4 5 1
row 6:   1  6  5 4  3 5  2  5  3  4 5  6 1
row 7: 1 7 6 5 4 7 3 5 7 2 7 5 3 7 4 5 6 7 1
```
The number of numbers in each row are 2, 3, 5, 7, 11, 13, 19...

Will they always be prime?

 No Solution Yet Submitted by Jer No Rating

Comments: ( Back to comment list | You must be logged in to post comments.)
 A classic puzzle Comment 3 of 3 |
The pattern of the numbers vaguely reminded me of something I had seen earlier, so I did some searching.  This puzzle appeared quite a long time ago on perplexus as Palindromic sequences.

 Posted by Brian Smith on 2017-09-19 23:23:09

 Search: Search body:
Forums (0)