cp's OEIS Frontend

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.

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.

Original entry on oeis.org

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

Views

Author

Dan Dart, Aug 25 2019

Keywords

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.
		

Programs

  • 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]
  • 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 *)