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 A194989 #13 Mar 30 2012 18:57:44 %S A194989 1,3,2,5,6,4,8,10,9,7,12,14,15,13,11,17,19,21,20,18,16,23,25,28,27,26, %T A194989 24,22,30,32,35,36,34,33,31,29,38,40,43,45,44,42,41,39,37,47,49,52,54, %U A194989 55,53,51,50,48,46,57,59,62,64,66,65,63,61,60,58,56,68,70,73 %N A194989 Inverse permutation of A194988; every positive integer occurs exactly once. %H A194989 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %t A194989 (See A194988.) %Y A194989 Cf. A194988, A194987, A194959. %K A194989 nonn %O A194989 1,2 %A A194989 _Clark Kimberling_, Sep 07 2011