Data update

Task/Tau-function/Haskell/tau-function-2.hs

@@ -0,0 +1,29 @@
+import Data.Numbers.Primes
+import Data.List (group, intercalate, transpose)
+import Data.List.Split (chunksOf)
+import Text.Printf
+
+----------------------- OEISA000005 ----------------------
+
+oeisA000005 :: [Int]
+oeisA000005 = tau <$> [1..]
+
+tau :: Integer -> Int
+tau = product . fmap (succ . length) . group . primeFactors
+
+
+--------------------------- TEST -------------------------
+
+main :: IO ()
+main = putStrLn $
+  (table "   " . chunksOf 10 . fmap show . take 100)
+  oeisA000005
+
+
+------------------------ FORMATTING ----------------------
+
+table :: String -> [[String]] -> String
+table gap rows =
+  let ws = maximum . fmap length <$> transpose rows
+      pw = printf . flip intercalate ["%", "s"] . show
+   in unlines $ intercalate gap . zipWith pw ws <$> rows