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 A194049 #8 Mar 19 2022 00:24:32 %S A194049 1,3,6,10,2,5,9,14,15,21,28,36,45,4,8,13,19,20,27,35,44,54,55,66,78,7, %T A194049 12,18,25,26,34,43,53,64,65,77,11,17,24,32,33,42,52,63,75,76,16,23,31, %U A194049 40,41,51,62,74,22,30,39,49,50,61,73,29,38,48,59,60,72 %N A194049 Inverse permutation to A194048; every positive integer occurs exactly once. %t A194049 (See A194048.) %Y A194049 Cf. A194048. %K A194049 nonn %O A194049 1,2 %A A194049 _Clark Kimberling_, Aug 13 2011