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 More about 1729 (Posted on 2012-01-04)
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.

Comments: ( Back to comment list | You must be logged in to post comments.)
 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

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