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 A194052 #12 Mar 19 2022 00:24:41 %S A194052 1,2,3,6,4,5,9,10,7,8,13,14,15,21,28,11,12,18,19,20,27,35,36,45,55,66, %T A194052 16,17,24,25,26,34,43,44,54,65,77,78,22,23,31,32,33,42,52,53,64,76,29, %U A194052 30,39,40,41,51,62,63,75 %N A194052 Inverse permutation to A194051; every positive integer occurs exactly once. %t A194052 (See A194051.) %Y A194052 Cf. A194051. %K A194052 nonn %O A194052 1,2 %A A194052 _Clark Kimberling_, Aug 13 2011