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 A129973 #12 Jan 31 2024 19:27:48
%S A129973 0,0,0,1,1,3,5,9,16,27,46,77,128,212,349,573,938,1532,2498,4067,6614,
%T A129973 10746,17446,28306,45903,74409,120577,195337,316379,512332,829527,
%U A129973 1342940,2173899,3518736,5695148,9217213,14916771,24139826,39064336
%N A129973 a(n) = A000045(n) - A000931(n).
%H A129973 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (1,2,0,-2,-1).
%F A129973 G.f.: x^4/((1-x-x^2)(1-x^2-x^3)). a(n)=a(n-1)+2*a(n-2)-2*a(n-4)-a(n-5). - _R. J. Mathar_, Oct 30 2008
%t A129973 LinearRecurrence[{1,2,0,-2,-1},{0,0,0,1,1},40] (* _Harvey P. Dale_, Jan 31 2024 *)
%o A129973 (PARI) a(n)=([0,1,0,0,0; 0,0,1,0,0; 0,0,0,1,0; 0,0,0,0,1; -1,-2,0,2,1]^(n-1)*[0;0;0;1;1])[1,1] \\ _Charles R Greathouse IV_, Oct 03 2016
%Y A129973 Cf. A000045, A000931.
%K A129973 nonn,easy,less
%O A129973 1,6
%A A129973 _Roger L. Bagula_, Jun 13 2007