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 A245599 #28 Apr 25 2020 09:58:02 %S A245599 1,11,91,731,5851,46811,374491,2995931,23967451,191739611,1533916891, %T A245599 12271335131,98170681051,785365448411,6282923587291,50263388698331, %U A245599 402107109586651,3216856876693211,25734855013545691,205878840108365531,1647030720866924251,13176245766935394011 %N A245599 Numbers m with A030101(m) XOR A030109(m) = m for the binary representation of m. %C A245599 Sequence consists of all numbers with binary representation 1(011)*. %H A245599 Colin Barker, <a href="/A245599/b245599.txt">Table of n, a(n) for n = 1..1001</a> %H A245599 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (9,-8). %F A245599 a(n) = 1(011)^(n-1) in binary representation. %F A245599 a(n) = (5*8^n - 12)/28. - _Giovanni Resta_, Apr 25 2020 %F A245599 From _Colin Barker_, Apr 25 2020: (Start) %F A245599 G.f.: x*(1 + 2*x) / ((1 - x)*(1 - 8*x)). %F A245599 a(n) = 9*a(n-1) - 8*a(n-2) for n>2. %F A245599 (End) %e A245599 A030101(11) = 13, A030109(11) = 6, and 13 XOR 6 = (1101)_2 XOR (0110)_2 = (1011)_2 = 11, so 11 is in the sequence. %t A245599 a[n_] := (5*8^n - 12)/28; Array[a, 20] (* _Giovanni Resta_, Apr 25 2020 *) %o A245599 (PARI) Vec(x*(1 + 2*x) / ((1 - x)*(1 - 8*x)) + O(x^20)) \\ _Colin Barker_, Apr 25 2020 %Y A245599 Cf. A007088, A030109, A030101. %K A245599 nonn,base,easy %O A245599 1,2 %A A245599 _Reinhard Muehlfeld_, Jul 27 2014 %E A245599 More terms from _Giovanni Resta_, Apr 25 2020