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 A213044 #14 Jul 25 2015 10:42:33
%S A213044 1,1,2,5,7,12,22,34,56,94,150,244,399,643,1042,1691,2733,4424,7164,
%T A213044 11588,18752,30348,49100,79448,128557,208005,336562,544577,881139,
%U A213044 1425716,2306866,3732582,6039448,9772042,15811490,25583532,41395035
%N A213044 Convolution of Fibonacci numbers and positive integers repeated three times (A000045 and A008620).
%H A213044 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (1, 1, 2, -2, -2, -1, 1, 1).
%F A213044 a(n) = a(n-1)+2*a(n-2)-2*a(n-3)-2*a(n-4)-a(n-5)+a(n-6)+a(n-7).
%F A213044 G.f.: 1/((1 - x - x^2)*(1 - x^3)^2).
%t A213044 f[x_] := (1 - x^3)^2; g[x] := 1 - x - x^2;
%t A213044 s = Normal[Series[1/(f[x] g[x]), {x, 0, 60}]]
%t A213044 c = CoefficientList[s, x] (* A213044 *)
%Y A213044 Cf. A213500.
%K A213044 nonn,easy
%O A213044 0,3
%A A213044 _Clark Kimberling_, Jun 10 2012