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 A227843 #8 Aug 24 2013 02:18:25
%S A227843 1,2,4,8,16,32,64,128,256,512,1024,2048,2592,4096,8192,16384,32768,
%T A227843 65536,131072,262144,524288,1048576,2097152,2458624,4194304,8388608,
%U A227843 16777216,33554432,67108864,134217728,268435456,536870912,1073741824,2147483648,4294967296,8589934592
%N A227843 Numbers n such that the binary XOR of the divisors of n (A178910(n)) is a binary repunit (A000225).
%C A227843 These are also numbers n such that A178910(n) >= A178910(i) for all i<n.
%C A227843 All powers of 2 are in the sequence. Terms that are not 2^x are 2592 and 2458624. No other non-2^x terms below 2^35.
%t A227843 fQ[n_] := Union@ IntegerDigits[ Fold[ BitXor[#1, #2] &, 0, Divisors@ n], 2] == {1}; Select[ Range@ 1000000000, fQ] (* _Robert G. Wilson v_, Aug 22 2013 *)
%Y A227843 Cf. A000225, A178910.
%K A227843 nonn,base
%O A227843 1,2
%A A227843 _Alex Ratushnyak_, Jul 06 2013