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 A085230 #15 Apr 13 2022 14:27:48 %S A085230 1,3,2,5,4,7,6,9,10,11,8,13,12,15,16,17,14,19,18,21,22,23,20,25,24,27, %T A085230 28,29,26,31,30,33,34,35,36,37,32,39,40,41,38,43,42,45,46,47,44,49,48, %U A085230 51,52,53,50,55,54,57,58,59,56,61,60,63,64,65,66,67,62,69,70 %N A085230 Inverse of A085229. %C A085230 Permutation of natural numbers: a(A085229(n)) = A085229(a(n)) = n. %C A085230 Odd numbers appear in order, at a(2k) for k > 0. - _Michael De Vlieger_, Apr 13 2022 %H A085230 Michael De Vlieger, <a href="/A085230/b085230.txt">Table of n, a(n) for n = 1..10000</a> %H A085230 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %t A085230 nn = 10000; c[_] = 0; a[1] = c[1] = 1; a[2] = 3; c[3] = u = 2; Do[k = u; While[Nand[c[k] == 0, CoprimeQ[a[i-1], k]], k++]; Set[{a[i], c[k]}, {k, i}]; If[a[i] == u, While[c[u] > 0, u++]], {i, 3, nn}]; Array[c, nn] (* _Michael De Vlieger_, Apr 13 2022 *) %Y A085230 Cf. A085229, A093715. %K A085230 nonn %O A085230 1,2 %A A085230 _Reinhard Zumkeller_, Jun 22 2003