is defined as the smallest number that can be expressed as a sum of two positive cube numbers in n distinct ways. The name is derived from a conversation in about 1919 involving mathematicians G. H. Hardy and Srinivasa Ramanujan. Hardy has ridden in taxi-cab No. 1729, and remarked that the number seemed to be rather a dull one. Ramanujan replied that the number was very interesting, as the smallest number expressible as the sum of two cubes in two different ways.