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 A167902 #4 Mar 30 2012 18:51:05 %S A167902 1,7,2,4,3,8,11,5,12,6,13,9,10,14,19,24,18,15,21,23,20,16,17,25,22,26, %T A167902 31,27,30,33,29,28,32,34,37,39,36,35,40,38,41,47,42,49,43,48,44,50,45, %U A167902 46,51,62,52,57,53,61,54,56,55,63,60,58,59,64,67,69,66,65,70,68,71,75 %N A167902 Inverse integer permutation to A075380. %C A167902 a(A075381(n)) = A075381(n); %C A167902 a(A075380(n)) = A075380(a(n)) = n; %C A167902 a(A167901(n)) = A167901(a(n)) = A121878(n). %H A167902 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %K A167902 nonn %O A167902 1,2 %A A167902 _Reinhard Zumkeller_, Nov 15 2009