43 lines
1.4 KiB
Markdown
43 lines
1.4 KiB
Markdown
# Perfect Numbers
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The Greek mathematician Nicomachus devised a classification scheme for natural numbers.
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The Greek mathematican Nicomachus devised a classification scheme for
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natural numbers, identifying each as belonging uniquely to the
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categories of _abundant_, _perfect_, or _deficient_. A perfect number
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equals the sum of its positive divisors — the pairs of numbers whose
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product yields the target number, excluding the number itself.
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- Perfect: Sum of factors = number
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- Abundant: Sum of factors > number
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- Deficient: Sum of factors < number
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The Aliquot sum is defined as the sum of the factors of a number not
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including the number itself.
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## Examples
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- 6 is a perfect number because its divisors are 1, 2, 3 and 6 = 1 + 2 +
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3.
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- 28 is perfect number because 28 = 1 + 2 + 4 + 7 + 14.
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- Prime numbers 7, 13, etc are Deficient by the Nicomachus
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classification.
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To run the tests simply run the command `go test` in the exercise directory.
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If the test suite contains benchmarks, you can run these with the `-bench`
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flag:
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go test -bench .
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For more detailed info about the Go track see the [help
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page](http://exercism.io/languages/go).
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## Source
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Taken from Chapter 2 of Functional Thinking by Neal Ford. [http://shop.oreilly.com/product/0636920029687.do](http://shop.oreilly.com/product/0636920029687.do)
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## Submitting Incomplete Problems
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It's possible to submit an incomplete solution so you can see how others have completed the exercise.
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