A222209 Inverse of permutation in A222208.

1, 3, 2, 5, 7, 4, 11, 9, 13, 17, 19, 6, 23, 29, 14, 15, 31, 8, 37, 21, 22, 41, 43, 10, 47, 53, 26, 25, 59, 28, 61, 27, 38, 67, 49, 12, 71, 73, 46, 35, 79, 33, 83, 57, 89, 97, 101, 18, 103, 51, 62, 69, 107, 16, 109, 55, 74, 113, 127, 34, 131, 137, 121, 45, 139

Offset

1,2

Comments

Permutation of the natural numbers A000027 with inverse permutation A222208.

Links

Alois P. Heinz, Table of n, a(n) for n = 1..10000

Index entries for sequences that are permutations of the natural numbers

Maple

b:= proc(n) false end:
g:= proc(n) option remember; local h, i;
      if n<3 then h:= 2*n-1 else g(n-1); h:= ilcm(map(g,
         numtheory[divisors](n) minus {1, n})[]) fi;
      for i while b(i*h) do od;
      b(i*h):= true; i*h
    end:
a:= proc() local t, a; t, a:= -1, proc() -1 end;
      proc(n) local h;
        while a(n) = -1 do
          t:= t+1; h:= g(t);
          if a(h) = -1 then a(h):= t fi
        od; a(n)
      end
    end():
seq(a(n), n=1..100);

Mathematica

terms = 100; b[1] = 1; b[2] = 3; b[n_] := b[n] = Module[{d, s, c, k}, d = Divisors[n] ~Complement~ {1, n}; For[s = Sort[Array[b, n - 1]]; c = Complement[ Range[ Last[s]], s]; k = If[c == {}, Last[s] + 1, First[c]], True, k++, If[FreeQ[s, k], If[AllTrue[d, Divisible[k, b[#]] &], Return[k]]]]]; a[n_] := a[n] = For[k = 1, True, k++, If[b[k] == n, Return[k]]]; Array[a, terms] (* Jean-François Alcover, Feb 22 2018 *)

Prog

(Haskell)
import Data.List (elemIndex)
import Data.Maybe (fromJust)
a222209 = (+ 1) . fromJust . (`elemIndex` a222208_list)
-- Reinhard Zumkeller, Feb 13 2013

Crossrefs

Cf. A000027, A211384, A222208.

Sequence in context: A375306 A375112 A069196 * A118320 A108918 A316472

Adjacent sequences: A222206 A222207 A222208 * A222210 A222211 A222212

Keyword

nonn,look

Author

Alois P. Heinz, Feb 12 2013

Status

approved