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 A191356 #10 Mar 30 2012 18:53:00 %S A191356 0,1,3,5,7,9,17,21,27,33,45,51,65,73,99,129,153,165,195,257,273,297, %T A191356 325,367,513,561 %N A191356 Interpret the terms of A069748 having only decimal digits 0 and 1 as binary numbers and then convert those numbers to decimal. %C A191356 May be the same sequence obtained from reading the terms of A002780 having only digits 0,1 in base 2 and converting to decimal. %e A191356 A069748(10)=10101 is the eighth number of A069748 having only digits 0 and 1. The binary number 10101 equals 21 in decimal. Thus a(8)=21. %Y A191356 Cf. A002780. %K A191356 nonn,base %O A191356 1,3 %A A191356 _Vladimir Shevelev_, May 31 2011