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 A276785 #25 Aug 12 2022 09:17:25
%S A276785 0,0,0,0,0,1,4,12,31,75,175,399,894,1975,4313,9330,20026,42704,90558,
%T A276785 191117,401654,841016,1755249,3652663,7581369,15698735,32438224,
%U A276785 66897295,137718495,283056086,580906268,1190538424,2436854280,4982012329,10174319500,20756971236,42306806495,86153127395
%N A276785 Number of binary strings of length n containing the substring 11011.
%H A276785 Aashir Shukla et al., <a href="http://math.stackexchange.com/questions/1920508/how-many-binary-strings-of-length-n-contain-within-it-the-substring-11011">How many Binary Strings of length N contain within it the substring '11011'?</a>, Mathematics Stack Exchange, circa Sep 09 2016.
%F A276785 G.f.: 1/(1-2*x) - (1+x^3+x^4)/(1-2*x+x^3-x^4-x^5) = x^5/((-1+2*x)*(x^5+x^4-x^3+2*x-1)).
%F A276785 Equals 2^n - A210021(n).
%F A276785 a(n) = Sum_{k>0} A277678(n,k). - _Alois P. Heinz_, Oct 26 2016
%Y A276785 Cf. A210021, A277678.
%K A276785 nonn,easy
%O A276785 0,7
%A A276785 _N. J. A. Sloane_, Oct 05 2016, following a suggestion from _Rick L. Shepherd_