A075383 Rearrangement of natural numbers so that next n numbers are each divisible by n.
1, 2, 4, 3, 6, 9, 8, 12, 16, 20, 5, 10, 15, 25, 30, 18, 24, 36, 42, 48, 54, 7, 14, 21, 28, 35, 49, 56, 32, 40, 64, 72, 80, 88, 96, 104, 27, 45, 63, 81, 90, 99, 108, 117, 126, 50, 60, 70, 100, 110, 120, 130, 140, 150, 160, 11, 22, 33, 44, 55, 66, 77, 121, 132, 143, 154, 84
Offset: 1
Examples
1; 2, 4; 3, 6, 9; 8, 12, 16, 20; 5, 10, 15, 25, 30; 18, 24, 36, 42, 48, 54; 7, 14, 21, 28, 35, 49, 56; 32, ...
Links
- R. Zumkeller, Table of n, a(n) for n = 1..10000 - _Reinhard Zumkeller_, Jun 22 2009
- Index entries for sequences that are permutations of the natural numbers
Crossrefs
Programs
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Haskell
import Data.List ((\\)) a075383 n k = a075383_tabl !! (n-1) !! (k-1) a075383_row n = a075383_tabl !! (n-1) a075383_tabl = f 1 [1..] where f x zs = ys : f (x + 1) (zs \\ ys) where ys = take x $ filter ((== 0) . (`mod` x)) zs a075383_list = concat a075383_tabl -- Reinhard Zumkeller, Nov 30 2015
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Mathematica
row[1] = {1}; row[n_] := row[n] = (For[rows = Join[row /@ Range[n-1]]; ro = {}; k = n, Length[ro] < n, k = k+n, If[FreeQ[rows, k], AppendTo[ro, k]]]; ro); Array[row, 12] // Flatten (* Jean-François Alcover, Apr 28 2017 *)
Extensions
More terms from Sascha Kurz, Jan 28 2003
Comments