What comes next:

2,

1729,

87,539,319,

6,963,472,309,248, ???

The answer, is 48,988,659,276,962,496. What, you didn't get it?

That number is the fifth Taxicab number. The *n*th Taxicab number is the lowest number that can be expressed as the sum of two cubes in *n* ways.

Ta(1)=2 - trival

1^{3}+1^{3}

Ta(2)=1729 - published by Frénicle de Bessy in 1657:

1^{3}+123^{3}

9^{3}+10^{3}

Ta(3)=87539319 - discovered by Leech in 1957

167^{3}+436^{3}

228^{3}+423^{3}

255^{3}+414^{3}

Ta(4)=6963472309248 - discovered by Rosenstiel, Dardis, and Rosenstiel in 1991

2421^{3}+19083^{3}

5436^{3}+18948^{3}

10200^{3}+18072^{3}

13322^{3}+16630^{3}

Ta(5)=48988659276962496 - discovered by David W. Wilson in 1997

38787^{3}+365757^{3}

107839^{3}+362753^{3}

205292^{3}+342952^{3}

221424^{3}+336588^{3}

231518^{3}+331954^{3}

These have become famous because of a certain mathematical incident... G. H. Hardy remembered once going to see Ramanujan in hospital, and had ridden in taxi-cab No. 1729, and remarked to Ramanujan that the number seemed to be rather dull. "No," he replied, "it is a very interesting number; it is the smallest number expressible as the sum of two cubes in two different ways."