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 A153435 #21 Apr 20 2024 10:19:41 %S A153435 11,1100,110011,11001100,1100110011,110011001100,11001100110011, %T A153435 1100110011001100,110011001100110011,11001100110011001100, %U A153435 1100110011001100110011,110011001100110011001100 %N A153435 Numbers with 2n binary digits where every run length is 2, written in binary. %C A153435 A043291 written in base 2. %H A153435 Vincenzo Librandi, <a href="/A153435/b153435.txt">Table of n, a(n) for n = 1..200</a> %H A153435 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (100,1,-100). %F A153435 From _Colin Barker_, Apr 19 2014: (Start) %F A153435 a(n) = (-101-99*(-1)^n+2^(3+2*n)*25^(1+n))/1818. %F A153435 a(n) = 100*a(n-1)+a(n-2)-100*a(n-3). %F A153435 G.f.: 11*x / ((x-1)*(x+1)*(100*x-1)).(End). %e A153435 n ... a(n) ....... A043291(n) %e A153435 1 ... 11 ............. 3 %e A153435 2 ... 1100 .......... 12 %e A153435 3 ... 110011 ........ 51 %e A153435 4 ... 11001100 ..... 204 %e A153435 5 ... 1100110011 ... 819 %p A153435 A153435:=n->(-101-99*(-1)^n+2^(3+2*n)*25^(1+n))/1818; seq(A153435(n), n=1..20); # _Wesley Ivan Hurt_, Apr 19 2014 %t A153435 Table[(-101 - 99*(-1)^n + 2^(3 + 2*n)*25^(1 + n))/1818, {n, 20}] (* _Wesley Ivan Hurt_, Apr 19 2014 *) %t A153435 CoefficientList[Series[11/((x - 1) (x + 1) (100 x - 1)), {x, 0, 30}], x] (* _Vincenzo Librandi_, Apr 20 2014 *) %o A153435 (PARI) Vec(11*x / ((x-1)*(x+1)*(100*x-1)) + O(x^100)) \\ _Colin Barker_, Apr 19 2014 %Y A153435 Cf. A043291. %K A153435 easy,nonn,base %O A153435 1,1 %A A153435 _Omar E. Pol_, Dec 26 2008