Taxicab Number

Just like 2 is the smallest natural number which can be represented a sum of two cubes in one way.

i.e. - 2 = 13 + 13

Find the smallest natural number representable in two different ways as a sum of two cubes.

8 Answers

11
Khyati ·

is it 1729?

13 + 123 = 1729

93 + 103 = 1729

just a try :)

71
Vivek @ Born this Way ·

It was given by Ramanujan while he was to die.!!!. Really What a great man he was!

11
Khyati ·

The number derives its name from the following story G. H. Hardy told about Ramanujan.

"Once, in the taxi from London, Hardy noticed its number, 1729. He must have thought

about it a little because he entered the room where Ramanujan lay in bed and, with scarcely

a hello, blurted out his disappointment with it. It was, he declared, 'rather a dull number,'

adding that he hoped that wasn't a bad omen. 'No, Hardy,' said Ramanujan, 'it is a very

interesting number. It is the smallest number expressible as the sum of two [positive] cubes

in two different ways' "

71
Vivek @ Born this Way ·

Ohh! No one giving importance to my Story!! . It was more good! :P

11
Shaswata Roy ·

People haven't yet found a no. which can be written as a sum of two numbers each to the power 5 in 2 ways.

i.e.:

a5+b5=c5+d5=x

The haven't yet found a single value for x.

11
Khyati ·

arey they have left something for us to prove and discover, sab kuchh wohi log kar jate toh

hum kya karte?

@ Shaswata you search some number which can be written as a sum of two numbers each

to the power 5 in 2 ways.

Wish you all the best :)

1
harsha121 ·

@shaswata it has been found out see down for such values

a=k
b=-k
c=m
d=-m

and u can keep any integral values for k,m......such as -2,-4,4,5,6,67..........

11
Shaswata Roy ·

You can only do it for positive natural numbers.

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