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 A265518 #4 Dec 09 2015 20:23:54 %S A265518 0,1,2,3,4,5,0,11,11,11,11,11,0,11,22,22,22,22,0,11,22,33,33,33,0,11, %T A265518 22,33,44,44,0,11,22,33,44,55,0,101,101,101,101,101,0,111,111,111,111, %U A265518 111,0,121,121,121,121,121,0,131,131,131,131,131,0,141,141,141,141,141,0,151,151,151,151,151,0,101,202,202 %N A265518 a(n) = largest base-6 palindrome m <= n such that every base-6 digit of m is <= the corresponding digit of n; m is written in base 6. %Y A265518 Sequences related to palindromic floor and ceiling: A175298, A206913, A206914, A261423, A262038, and the large block of consecutive sequences beginning at A265509. %K A265518 nonn,base %O A265518 0,3 %A A265518 _N. J. A. Sloane_, Dec 09 2015