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

Home > Numbers
Surf City Semiprimes (Posted on 2011-09-27) Difficulty: 2 of 5

Let n be some arbitrarily huge number; call each prime between 1 and n a 'GIRL'; call each even semiprime between 1 and n a 'BOY'.

Prove that there are two GIRLs for every BOY.

(An even semiprime is a composite number one of whose two prime factors is 2.)

See The Solution Submitted by broll    
No Rating

Comments: ( Back to comment list | You must be logged in to post comments.)
I don't think it's true. Maybe I do. | Comment 2 of 4 |
BOYs can be restated as the number of primes between 1 and n/2

Then two GIRLs for every BOY implies there are the same number of primes between 1 and n/2 as between n/2 and n.

This doesn't seem possible as the primes get more sparse.  There are fewer primes from n/2 to n.  So it would not seem to be true.

The prime number counting function is roughly the Logarithmic integral function.  If the shape of this function becomes basically a straight line this would imply the proof.  Well the natural logarithm function does flatten out as n increases.   So maybe it is true.

  Posted by Jer on 2011-09-27 11:13:57
Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (3)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2024 by Animus Pactum Consulting. All rights reserved. Privacy Information