Guest Posted January 16, 2011 Report Share Posted January 16, 2011 what is so special about 1729? Quote Link to comment Share on other sites More sharing options...
0 wolfgang Posted January 16, 2011 Report Share Posted January 16, 2011 what is so special about 1729? 1729 = 1^3 + 12^3 = 9^3 + 10^3 Quote Link to comment Share on other sites More sharing options...
0 dark_magician_92 Posted January 16, 2011 Report Share Posted January 16, 2011 what is so special about 1729? its the smallest no. which can be expressed in more than 1 way as sum of cubes of 2 integers. 12,1 and 10,9 Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 16, 2011 Report Share Posted January 16, 2011 1729=7*(7+6)*(7+6+6)=7*13*19 Quote Link to comment Share on other sites More sharing options...
0 Aaryan Posted January 16, 2011 Report Share Posted January 16, 2011 It's the only whole number between 172 and 1730. Stupid, but true. Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 16, 2011 Report Share Posted January 16, 2011 it is the smallest number expressible as the sum of two cubes in two different ways Quote Link to comment Share on other sites More sharing options...
0 Aaryan Posted January 16, 2011 Report Share Posted January 16, 2011 my mistake. it's the only number between. 1728 and 1730 Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 17, 2011 Report Share Posted January 17, 2011 1729=7*(7+6)*(7+6+6)=7*13*19 I will check this. good Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 17, 2011 Report Share Posted January 17, 2011 its the smallest no. which can be expressed in more than 1 way as sum of cubes of 2 integers. 12,1 and 10,9 OK Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 17, 2011 Report Share Posted January 17, 2011 my mistake. it's the only number between. 1728 and 1730 this is not the reasoning Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 17, 2011 Report Share Posted January 17, 2011 it is the smallest number expressible as the sum of two cubes in two different ways very good Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 17, 2011 Report Share Posted January 17, 2011 1729 = 1^3 + 12^3 = 9^3 + 10^3 good Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 17, 2011 Report Share Posted January 17, 2011 its the smallest no. which can be expressed in more than 1 way as sum of cubes of 2 integers. 12,1 and 10,9 IT is called Ramanujan's number Quote Link to comment Share on other sites More sharing options...
0 Aaryan Posted January 17, 2011 Report Share Posted January 17, 2011 it's true. Quote Link to comment Share on other sites More sharing options...
0 Aaryan Posted January 17, 2011 Report Share Posted January 17, 2011 this is not the reasoning It still works, though. Quote Link to comment Share on other sites More sharing options...
0 Guest Posted April 16, 2011 Report Share Posted April 16, 2011 I have another answer also If you sum the digits of the number i.e.1+7+2+9=19 and now multiply it with its inverse i.e. 19*91=1729 18 is the only another number which follows this property(in my knowledge) Quote Link to comment Share on other sites More sharing options...
0 fabpig Posted April 16, 2011 Report Share Posted April 16, 2011 my mistake. it's the only number between. 1728 and 1730 After extensive research, I can confirm that Aaryan is correct. Well done, indeed. It's also the year I was born. Quote Link to comment Share on other sites More sharing options...
0 fabpig Posted April 16, 2011 Report Share Posted April 16, 2011 I have another answer also If you sum the digits of the number i.e.1+7+2+9=19 and now multiply it with its inverse i.e. 19*91=1729 18 is the only another number which follows this property(in my knowledge) It works for 1458, too (18*81) Quote Link to comment Share on other sites More sharing options...
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what is so special about 1729?
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