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 A135138 #21 Jan 02 2024 08:57:01
%S A135138 0,0,1,0,5,2,25,20,129,150,685,1008,3725,6410,20641,39500,116025,
%T A135138 238782,659125,1425960,3773189,8448050,21717865,49786628,125485425,
%U A135138 292368870,727000381,1712815200,4219739645,10018076762,24524328625,58529863100
%N A135138 a(n) = 5*a(n-2) + 2*a(n-3).
%C A135138 a(n+2), n>=0, is the (5,2)-Padovan sequence p(5,2;n)with o.g.f. 1/(1-5*x^2-2*x^3). See A000931(n+3) ((1,1)-Padovan), and the W. Lang link given there, also for a combinatorial interpretation. - _Wolfdieter Lang_, Jun 28 2010
%H A135138 G. C. Greubel, <a href="/A135138/b135138.txt">Table of n, a(n) for n = 0..1000</a>
%H A135138 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (0,5,2).
%F A135138 From _R. J. Mathar_, Feb 15 2008: (Start)
%F A135138 O.g.f.: -x^2 / ( (2*x+1)*(x^2+2*x-1) ).
%F A135138 a(n) = [(-2)^n + A078343(n)]/7. (End)
%t A135138 a = {0, 0, 1}; Do[AppendTo[a, 5*a[[ -2]] + 2*a[[ -3]]], {40}]; a (* _Stefan Steinerberger_, Feb 15 2008 *)
%t A135138 LinearRecurrence[{0, 5, 2}, {0, 0, 1}, 100] (* _G. C. Greubel_, Sep 28 2016 *)
%Y A135138 Cf. A135139.
%K A135138 nonn,easy
%O A135138 0,5
%A A135138 _Paul Curtz_, Feb 13 2008
%E A135138 More terms from _R. J. Mathar_ and _Stefan Steinerberger_, Feb 15 2008