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 A031950 #18 Aug 10 2021 18:46:47 %S A031950 5,7,8,9,10,11,13,14,15,16,17,19,20,21,22,23,25,26,30,32,33,34,36,37, %T A031950 41,43,46,49,50,52,56,57,60,61,63,64,67,68,72,74,75,78,81,83,87,88,90, %U A031950 91,92,94,98,99,100,104,106,109,112,114,118,119 %N A031950 Numbers with exactly two distinct base-5 digits. %H A031950 <a href="/index/Ar#5-automatic">Index entries for 5-automatic sequences</a>. %t A031950 Select[Range[150],Length[Union[IntegerDigits[#,5]]]==2&] (* _Harvey P. Dale_, Apr 13 2011 *) %Y A031950 Cf. A007091. %K A031950 nonn,base,easy %O A031950 1,1 %A A031950 _Clark Kimberling_