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Generalized taxicab number

In mathematics, the generalized taxicab number Taxicab(k, j, n) is the smallest number which can be expressed as the sum of j kth positive powers in n different ways. For k = 3 and j = 2, they coincide with Taxicab numbers.

It has been shown by Euler that

Taxicab(4,2,2) = 635318657 = 594 + 1584 = 1334 + 1344

However, Taxicab(4, 3, n) is not known for any n >= 2, and neither is Taxicab(5, 2, n); in fact, no positive integer is known at all which can be written as the sum of three fourth powers or two fifth powers in more than one way.

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01-04-2007 01:18:14
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