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 A113218 #13 Feb 16 2025 08:32:59 %S A113218 0,1,2,3,4,5,6,7,8,9,11,10,13,12,15,14,17,16,20,18,22,19,24,21,26,23, %T A113218 29,25,31,27,33,28,35,30,38,32,40,34,42,36,44,37,47,39,49,41,51,43,53, %U A113218 45,56,46,58,48,60,50,62,52,65,54,67,55,69,57,71,59,74,61,76,63,78,64,80 %N A113218 Lexicographically earliest permutation of the natural numbers with alternating parities of digital roots in decimal representation. %C A113218 inverse: A113220; A113219 = a(a(n)); %C A113218 A113217(a(n)) = A000035(n). %H A113218 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %H A113218 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/DigitalRoot.html">Digital Root</a> %Y A113218 Cf. A010888. %K A113218 nonn,easy,base %O A113218 0,3 %A A113218 _Reinhard Zumkeller_, Oct 18 2005