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 A257465 #4 Apr 25 2015 10:06:38 %S A257465 1,2,4,3,7,5,9,13,11,6,8,10,17,21,15,12,14,19,23,25,27,31,16,18,29,22, %T A257465 35,20,37,33,39,24,43,26,47,28,41,49,32,45,30,51,53,55,57,36,61,34,38, %U A257465 64,59,40,66,68,72,44,70,76,42,48,74,78,80,46,50,84,82 %N A257465 Inverse permutation to A175498. %H A257465 Reinhard Zumkeller, <a href="/A257465/b257465.txt">Table of n, a(n) for n = 1..10000</a> %H A257465 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %o A257465 (Haskell) %o A257465 import Data.List (elemIndex); import Data.Maybe (fromJust) %o A257465 a257465 = (+ 1) . fromJust . (`elemIndex` a175498_list) %Y A257465 Cf. A175498. %K A257465 nonn %O A257465 1,2 %A A257465 _Reinhard Zumkeller_, Apr 25 2015