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

Home > Numbers
More about 1729 (Posted on 2012-01-04) Difficulty: 3 of 5
Much was said about 1729 a.k.a. Ramanujan number.or a taxicab number.
1729 is also a Carmichael number and the first absolute Euler pseudoprime, a sphenic number, a Zeisel number etc etc

  Please note the following (and solve):
  1. 1729 is one of four positive integers (with the others being A, B and the trivial case 1) which, when its digits are added together, produces a sum which, when multiplied by its reversal, yields the original number:
1 + 7 + 2 + 9 = 19 ; 19*91 = 1729
Find A and B.

2. 1729= xyz, where x,y and z are integer members of an arithmetic progression.
Find these members.

3. 1729 can be expressed (in more than one way) as a sum of distinct Fibonacci numbers
List all the expressions.
 

See The Solution Submitted by Ady TZIDON    
Rating: 5.0000 (4 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Solution correct a typo Comment 8 of 8 |

CORRECTION


sod* its reversal =          should be:

9 * 9 = 81  ...sod(81)=9
 18* 81 =1458   ...sod(1458)=18
 19* 91 = 1729   ...sod(1729)=19

 


  Posted by Ady TZIDON on 2017-06-21 09:48:38
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 (5)
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