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 A118128 #5 Oct 02 2013 15:12:50 %S A118128 1,3,7,19,137,139,155,379,1509,4877,9509,13015,44819,75595,245027, %T A118128 804463,1082053,1154293,5802669,10186839,52333761,81509017,130656729, %U A118128 375417331,476594459,1955429145,9051994251,12788782787 %N A118128 Numbers n such that the sum of the first n odd composites is palindromic in base 2. %e A118128 The sum of the first 19 odd composites, when written in binary, is the palindrome 1101111011, so 19 is in the sequence. %Y A118128 Cf. A058848 (palindromic in base 10). %K A118128 nonn,base %O A118128 1,2 %A A118128 _Ryan Propper_, May 12 2006