Definition:Taxicab Number

Definition
A taxicab number is a positive integer which can be expressed as the sum of $2$ cubes in $2$ different ways.

Also defined as
The usual definition of the $n$th taxicab number is the smallest positive integer which can be expressed as the sum of $2$ cubes in $n$ different ways.

However, the name Hardy-Ramanujan number is also used for that specific concept, which is preferred on to reduce ambiguity and confusion.

Also known as
The name is sometimes hyphenated: taxi-cab number.

Also see

 * Definition:Hardy-Ramanujan Number