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jadlr/Repdigit.hs

Created July 19, 2016 20:24
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Repdigit sequence calculation in haskell
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Repdigit.hs
module Repdigit where
-- https://oeis.org/A010785
repdigit :: Integer -> Integer
repdigit n = (n - 9 * floor ((fromInteger n - 1) / 9)) * (10 ^ floor ((fromInteger n + 8) / 9) - 1) `quot` 9
repdigits :: [Integer]
repdigits = go 0
where go n = repdigit n : go (n + 1)
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jadlr commented Jul 19, 2016 

*Repdigit> repdigit 100
111111111111
*Repdigit> take 30 repdigits
[0,1,2,3,4,5,6,7,8,9,11,22,33,44,55,66,77,88,99,111,222,333,444,555,666,777,888,999,1111,2222]

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