A309979 Hash Parker numbers: Integers whose real 32nd root's first six nonzero digits (after the decimal point) rearranged in ascending order are equal to 234477.
4, 1191, 2340, 4915, 8101, 8703, 13937, 13952, 14029, 14041, 25111, 25127, 26062, 26203, 26324, 26479, 26490, 27934, 28077, 28195, 50506, 50536, 52216, 52359, 52892, 55703, 55957, 56030, 56059, 56075, 56178, 56244, 56566, 56577, 74747, 75877, 75952, 75996, 80752, 80764, 80765
Offset: 1
Examples
4^(1/32) = 1.0442737824274138... Rearranging 442737 in ascending order gives 234477. 1191^(1/32) = 1.2477346... -> 247734 -> 234477; 2340^(1/32) = 1.2743478... -> 274347 -> 234477.
Links
- Matt Parker's YouTube Video, The A4 Paper Puzzle
Programs
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Haskell
import Data.List hash :: Double -> Inthash = read . sort . take 6 . filter (/='0') . drop 1 . dropWhile (/='.') . show . (** 0.03125) main :: IO ()main = print $ map (floor . fst) . filter ((==234477) . snd) $ map (\x -> (x, hash x)) [2..1000000]
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Mathematica
Select[Range[81000],With[{c=RealDigits[Surd[#,32],10,20]/.(0->Nothing)},Sort[Take[Drop[c[[1]],c[[2]]],6]]=={2,3,4,4,7,7}]&]//Quiet (* Harvey P. Dale, Jun 22 2025 *)