This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A309979 #14 Jun 22 2025 12:23:23
%S A309979 4,1191,2340,4915,8101,8703,13937,13952,14029,14041,25111,25127,26062,
%T A309979 26203,26324,26479,26490,27934,28077,28195,50506,50536,52216,52359,
%U A309979 52892,55703,55957,56030,56059,56075,56178,56244,56566,56577,74747,75877,75952,75996,80752,80764,80765
%N 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.
%H A309979 Matt Parker's YouTube Video, <a href="https://www.youtube.com/watch?v=SOgn6J12NWE">The A4 Paper Puzzle</a>
%e A309979 4^(1/32) = 1.0442737824274138...
%e A309979 Rearranging 442737 in ascending order gives 234477.
%e A309979 1191^(1/32) = 1.2477346... -> 247734 -> 234477;
%e A309979 2340^(1/32) = 1.2743478... -> 274347 -> 234477.
%t A309979 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 *)
%o A309979 (Haskell)
%o A309979 import Data.List
%o A309979 hash :: Double -> Inthash = read . sort . take 6 . filter (/='0') . drop 1 . dropWhile (/='.') . show . (** 0.03125)
%o A309979 main :: IO ()main = print $ map (floor . fst) . filter ((==234477) . snd) $ map (\x -> (x, hash x)) [2..1000000]
%K A309979 nonn,base
%O A309979 1,1
%A A309979 _Dan Dart_, Aug 25 2019