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 A083850 #5 Sep 05 2020 15:53:17 %S A083850 1,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,0,0,2,0,0,0,0,0,0,0,0,0,0,0,2, %T A083850 0,0,0,0,0,0,0,0,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,2,0,0,0,0,0,0,0,0,0,0, %U A083850 0,0,1,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0 %N A083850 Exponent of highest power of 11 dividing the n-th decimal palindrome; a(0) = 1. %t A083850 IntegerExponent[#,11]&/@Select[Range[0,1000],PalindromeQ]/.\[Infinity]->1 (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Sep 05 2020 *) %Y A083850 Cf. A083851, A083852, A002113, A008593. %K A083850 nonn,base %O A083850 0,22 %A A083850 _Reinhard Zumkeller_, May 06 2003