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 A143281 #11 Apr 29 2017 04:15:08
%S A143281 0,0,0,1,2,4,8,15,27,48,84,145,248,421,710,1191,1989,3309,5487,9073,
%T A143281 14966,24634,40472,66384,108729,177858,290610,474364,773615,1260643,
%U A143281 2052818,3340662,5433345,8832432,14351403,23309326,37844645,61423513,99663191,161665653
%N A143281 Number of binary words of length n containing at least one subword 101 and no subword 11.
%H A143281 Alois P. Heinz, <a href="/A143281/b143281.txt">Table of n, a(n) for n = 0..1000</a>
%F A143281 G.f.: x^3/((x^2+x-1)*(x^3+x-1)).
%F A143281 a(n) = A000045(n+2)-A000930(n+2).
%e A143281 a(6)=8 because 8 binary words of length 6 have at least one substring 101 and no substring 11: 000101, 001010, 010100, 101000, 010101, 101010, 101001, 100101.
%p A143281 a:= n-> coeff(series(x^3/((x^2+x-1)*(x^3+x-1)), x, n+1), x, n):
%p A143281 seq(a(n), n=0..60);
%t A143281 CoefficientList[Series[x^3/((x^2+x-1)*(x^3+x-1)), {x, 0, 50}], x] (* _G. C. Greubel_, Apr 28 2017 *)
%o A143281 (PARI) x='x+O('x^50); concat([0,0,0], Vec(x^3/((x^2+x-1)*(x^3+x-1)))) \\ _G. C. Greubel_, Apr 28 2017
%Y A143281 Cf. A000045, A000930, first column of A143291.
%K A143281 nonn
%O A143281 0,5
%A A143281 _Alois P. Heinz_, Aug 04 2008