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 A116942 #10 Jun 28 2013 02:44:27 %S A116942 0,1,3,2,4,6,5,7,10,8,11,9,12,15,13,16,14,17,21,18,22,19,23,20,24,28, %T A116942 25,29,26,30,27,31,36,32,37,33,38,34,39,35,40,45,41,46,42,47,43,48,44, %U A116942 49,55,50,56,51,57,52,58,53,59,54,60,66,61,67,62,68,63,69,64,70,65,71,78 %N A116942 Permutation of the natural numbers in conjunction with A116939 and A003056. %C A116942 Inverse: A116941; %C A116942 A116939(n) = A003056(a(n)). %H A116942 Reinhard Zumkeller, <a href="/A116942/b116942.txt">Table of n, a(n) for n = 0..10000</a> %H A116942 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %o A116942 (Haskell) %o A116942 import Data.List (elemIndex) %o A116942 import Data.Maybe (fromJust) %o A116942 a116942 = fromJust . (`elemIndex` a116941_list) %o A116942 -- _Reinhard Zumkeller_, Jun 28 2013 %K A116942 nonn %O A116942 0,3 %A A116942 _Reinhard Zumkeller_, Feb 27 2006