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 A306233 #13 Jan 31 2019 19:37:16 %S A306233 1,2,3,5,6,4,12,8,9,20,17,24,33,13,22,11,69,37,51,7,14,88,109,23,67, %T A306233 49,232,40,107,25,91,16,97,119,26,53,290,153,41,21,350,39,253,208,56, %U A306233 112,669,28,270,614,30,76,667,388,95,43,464,675,671,32,796,92,45 %N A306233 Inverse to A306231. %H A306233 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %e A306233 A306231(39) = 42, hence a(42) = 39. %Y A306233 Cf. A306231. %K A306233 nonn,base %O A306233 1,2 %A A306233 _Rémy Sigrist_, Jan 31 2019