perplexus.info :: Numbers : Ulam numbers II

Ulam numbers II (Posted on 2017-11-18)

There is a finite number of Ulam numbers n, such that n+1 is also an Ulam number.

List all such pairs.

Submitted by Ady TZIDON

No Rating

Solution: (Hide)

1,2,3,47 are the only values of x such that x and x+1 are both Ulam numbers.
No proof of completeness.
Checked for the first 28 billion Ulam numbers as of 2016.(OEIS)

Comments: ( You must be logged in to post comments.)

	Subject	Author	Date
	computer "solution"	Charlie	2017-11-18 16:10:30

Please log in:

Login:
Password:
Remember me:

Sign up! \| Forgot password

Search:

Search body:

Forums (1)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (22)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:


perplexus dot info