Perfect numbers: Difference between revisions
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(→{{header|Haskell}}: Added a Haskell variant) |
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mapM_ print $ take 10 perfect |
mapM_ print $ take 10 perfect |
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mapM_ (print . (\x -> (x, isPerfect x))) [6, 27, 28, 29, 496, 8128, 8129]</lang> |
mapM_ (print . (\x -> (x, isPerfect x))) [6, 27, 28, 29, 496, 8128, 8129]</lang> |
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or, using a simple restriction of the search space: |
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<lang haskell>isPerfect :: Int -> Bool |
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isPerfect n = |
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let lows = filter ((0 ==) . rem n) [1 .. floor (sqrt (fromIntegral n))] |
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in 1 < n && |
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quot |
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(sum $ |
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lows ++ |
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concatMap |
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(\x -> |
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let y = quot n x |
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in [ y |
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| x /= y ]) |
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lows) |
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2 == |
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n |
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main :: IO () |
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main = print $ filter isPerfect [1 .. 10000]</lang> |
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{{Out}} |
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<pre>[6,28,496,8128]</pre> |
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=={{header|HicEst}}== |
=={{header|HicEst}}== |
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