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 A265528 #6 Dec 09 2015 21:39:58 %S A265528 0,1,11,101,111,1001,1001,1001,1111,10001,10001,10101,10101,10101, %T A265528 11011,11011,11111,100001,100001,100001,100001,100001,100001,101101, %U A265528 101101,101101,110011,110011,110011,110011,110011,110011,111111,1000001,1000001,1000001,1000001,1001001,1001001,1001001,1001001,1001001,1001001 %N A265528 Largest base-2 palindrome m <= 2n, written in base 2. %Y A265528 Sequences related to palindromic floor and ceiling: A175298, A206913, A206914, A261423, A262038, and the large block of consecutive sequences beginning at A265509. %K A265528 nonn,base %O A265528 0,3 %A A265528 _N. J. A. Sloane_, Dec 09 2015