Calmo numbers: Difference between revisions
→{{header| Haskell}}: Added a draft in Haskell
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(→{{header| Haskell}}: Added a draft in Haskell) |
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957 [3 11 29 33 87 319] [43 439]
</pre>
=={{header|Haskell}}==
<syntaxhighlight lang=Haskell>import Data.List (group, sort)
import Data.List.Split (chunksOf)
import Data.Numbers.Primes (isPrime, primeFactors)
---------------------- CALMO NUMBERS ---------------------
isCalmo :: Int -> Bool
isCalmo n =
let xs = properDivisors n
m = length xs
in m > 3
&& 0 == mod (pred m) 3
&& all (isPrime . sum) (chunksOf 3 $ tail xs)
--------------------------- TEST -------------------------
main :: IO ()
main = print $ takeWhile (< 1000) $ filter isCalmo [1 ..]
------------------------- GENERIC ------------------------
properDivisors :: Int -> [Int]
properDivisors =
init
. sort
. foldr --
(flip ((<*>) . fmap (*)) . scanl (*) 1)
[1]
. group
. primeFactors</syntaxhighlight>
{{Out}}
<pre>[165,273,385,399,561,595,665,715,957]</pre>
=={{header|J}}==
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