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32 lines
759 B
32 lines
759 B
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Exercise 3.71: Numbers that can be expressed as
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the sum of two cubes in more than one way are sometimes called
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Ramanujan numbers, in honor of the mathematician Srinivasa
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Ramanujan.198 Ordered streams of pairs provide an elegant
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solution to the problem of computing these numbers. To find a number that can
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be written as the sum of two cubes in two different ways, we need only generate
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the stream of pairs of integers
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(
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i
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,
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j
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)
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weighted according to the sum
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i
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3
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+
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j
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3
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(see Exercise 3.70), then search the stream for two
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consecutive pairs with the same weight. Write a procedure to generate the
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Ramanujan numbers. The first such number is 1,729. What are the next five?
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