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 A100116 #7 Mar 30 2012 18:50:48 %S A100116 1,2,5,4,7,3,13,8,9,10,19,12,23,11,6,16,30,18,41,20,14,17,47,24,25,26, %T A100116 27,28,57,15,61,32,21,29,34,36,66,39,22,40,71,33,87,44,45,46,94,48,49, %U A100116 50,31,52,102,54,35,56,42,55,110,60,115,62,63,64,37,43,123,68,51,38,139 %N A100116 If n is squarefree then A100114(A100112(n)) else n. %C A100116 Permutation of the natural numbers with inverse A100115; %C A100116 a(A013929(n)) = A013929(n). %H A100116 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %Y A100116 Cf. A005117. %K A100116 nonn %O A100116 1,2 %A A100116 _Reinhard Zumkeller_, Nov 07 2004