48 lines
1.2 KiB
Haskell
48 lines
1.2 KiB
Haskell
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import Control.Monad (replicateM)
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import Data.Numbers.Primes (isPrime)
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--------------------- CYCLOPS NUMBERS --------------------
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cyclops :: [Integer]
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cyclops = [0 ..] >>= go
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where
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go 0 = [0]
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go n =
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(\s -> read s :: Integer)
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<$> (fmap ((<>) . (<> "0")) >>= (<*>))
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(replicateM n ['1' .. '9'])
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blindPrime :: Integer -> Bool
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blindPrime n =
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let s = show n
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m = quot (length s) 2
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in isPrime $
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(\t -> read t :: Integer)
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(take m s <> drop (succ m) s)
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palindromic :: Integer -> Bool
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palindromic = ((==) =<< reverse) . show
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-------------------------- TESTS -------------------------
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main :: IO ()
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main =
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(putStrLn . unlines)
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[ "First 50 Cyclops numbers – A134808:",
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unwords (show <$> take 50 cyclops),
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"",
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"First 50 Cyclops primes – A134809:",
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unwords $ take 50 [show n | n <- cyclops, isPrime n],
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"",
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"First 50 blind prime Cyclops numbers – A329737:",
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unwords $
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take
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50
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[show n | n <- cyclops, isPrime n, blindPrime n],
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"",
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"First 50 prime palindromic cyclops numbers – A136098:",
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unwords $
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take
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50
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[show n | n <- cyclops, isPrime n, palindromic n]
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]
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