Anecdote, first-person

The dull number in the taxi

Coincidence · Told by Hardy, 1919 or after · A taxi, then a nursing home in Putney

1729

DocumentA number. Hardy’s story. Ramanujan’s reply as Hardy printed it.

Hardy thought the number dull. Ramanujan did not.

Hardy took a taxi to visit Ramanujan, ill. The number was 1729. Hardy said it was dull. Ramanujan, on Hardy’s telling, answered at once: the smallest number expressible as the sum of two cubes in two ways. The field was already in him. The taxi only named it.

The number did not become interesting because it arrived. It arrived in a mind that had somewhere to put it.

Concordance

The thing
A visit, a taxi number, a mind that had already lived with 1729 as two cubes two ways.
Seen
1729 = 1³+12³ = 9³+10³.
Sourced
G. H. Hardy, writings on Ramanujan, including Ramanujan: Twelve Lectures.
Miss
We have Hardy’s telling. Ramanujan did not write this scene.
One question remains
What was already in Ramanujan before the taxi?