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 A261794 #14 Sep 09 2020 11:29:28 %S A261794 1,2,1,1,1,1,1,1,1,1,2,2,3,2,2,2,2,2,2,2,1,3,1,1,1,1,1,1,1,1,1,2,1,1, %T A261794 1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1,1,2,1,1,1,1,1,1, %U A261794 1,1,1,2,1,1,1,1,1,1,1,1,1,2,1,1,1,1 %N A261794 a(n) is the smallest nonzero number that is not a substring of n in decimal representation. %C A261794 A261795(n) = a(A261793(n)). %H A261794 Reinhard Zumkeller, <a href="/A261794/b261794.txt">Table of n, a(n) for n = 0..10000</a> %o A261794 (Haskell) %o A261794 import Data.List (isInfixOf) %o A261794 a261794 x = f $ tail a031298_tabf where %o A261794 f (cs:css) = if isInfixOf cs (a031298_row x) %o A261794 then f css else foldr (\d v -> 10 * v + d) 0 cs %Y A261794 Cf. A007089, A031298, A261795, A261793, A261461, A261787. %K A261794 nonn,base %O A261794 0,2 %A A261794 _Reinhard Zumkeller_, Sep 01 2015 %E A261794 Name corrected by _Álvar Ibeas_, Sep 08 2020