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 A065254 #13 Jan 22 2020 20:18:45
%S A065254 2,7,1,3,5,8,14,12,6,51,4,17,10,20,9,21,30,19,13,55,38,22,16,24,11,23,
%T A065254 40,27,15,66,41,29,18,37,32,42,48,35,31,72,50,34,25,58,49,70,57,36,39,
%U A065254 78,69,54,26,60,52,73,67,53,43,86,95,64,28,61,62,76,97,68,45,98,96,74
%N A065254 "Inverse" to A065253.
%C A065254 The sequence would be a permutation of the naturals if each of the digits 0,1,..,9 occur infinitely often in the decimal expansion of Pi. "Inverse": A065253.
%H A065254 Reinhard Zumkeller, <a href="/A065254/b065254.txt">Table of n, a(n) for n = 1..10000</a>
%H A065254 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>
%t A065254 terms = 100; Clear[cnt]; cnt[_] = n = 0;
%t A065254 Do[a065253[++n] = 10(++cnt[k]-1)+k, {k, RealDigits[Pi, 10, terms][[1]]}];
%t A065254 Sort[{a065253[#], #}& /@ Range[terms]][[All, 2]] // Rest (* _Jean-François Alcover_, Jan 22 2020 *)
%o A065254 (Haskell)
%o A065254 import Data.List (elemIndex); import Data.Maybe (fromJust)
%o A065254 a065254 = (+ 1) . fromJust . (`elemIndex` a065253_list)
%o A065254 -- _Reinhard Zumkeller_, Jul 14 2013
%Y A065254 Cf. A065253.
%K A065254 base,nice,nonn
%O A065254 1,1
%A A065254 Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Oct 26 2001