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 A084489 #9 Jul 29 2017 13:30:43 %S A084489 1,2,3,5,4,6,7,8,9,11,10,13,12,14,16,17,15,20,18,19,23,22,21,24,25,26, %T A084489 27,28,29,31,30,32,34,33,35,36,38,39,37,40,43,41,42,44,47,46,45,49,48, %U A084489 50,51,53,52,55,54,57,58,56,59,61,62,63,60,65,67,64,66,69,71,70,68,74 %N A084489 a(n) = n + A084501(n) - 3. %H A084489 A. Karttunen, <a href="/A084507/a084507.scm.txt">Scheme-program for computing this sequence</a> %H A084489 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %Y A084489 Inverse: A084490. Cf. A084491, A084453, A084459, A084493, A084497. %K A084489 nonn %O A084489 1,2 %A A084489 _Antti Karttunen_, Jun 02 2003