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 A265512 #4 Dec 09 2015 20:16:18 %S A265512 0,1,2,0,11,11,0,11,22,0,101,101,0,111,111,0,121,121,0,101,202,0,111, %T A265512 212,0,121,222,0,1001,1001,0,1001,1001,0,1001,1001,0,1001,1001,0,1111, %U A265512 1111,0,1111,1111,0,1001,1001,0,1111,1111,0,1221,1221,0,1001,2002,0,1001,2002,0,1001,2002,0,1001,2002,0,1111,2112 %N A265512 a(n) = largest base-3 palindrome m <= n such that every base-3 digit of m is <= the corresponding digit of n; m is written in base 3. %Y A265512 Sequences related to palindromic floor and ceiling: A175298, A206913, A206914, A261423, A262038, and the large block of consecutive sequences beginning at A265509. %K A265512 nonn,base %O A265512 0,3 %A A265512 _N. J. A. Sloane_, Dec 09 2015