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 A134720 #22 Aug 31 2025 18:35:26
%S A134720 0,0,0,2,2,4,12,16,28,86,114,200,616,816,1432,4410,5842,10252,31572,
%T A134720 41824,73396,226030,299426,525456,1618192,2143648,3761840,11584946,
%U A134720 15346786,26931732,82938844,109870576,192809420,593775046,786584466,1380359512,4250949112
%N A134720 Even Padovan numbers.
%H A134720 <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,7,0,0,1,0,0,1).
%F A134720 a(n) = 2 * A135619(n).
%F A134720 G.f.: -2*x^4*(x^4-x^3+2*x^2+x+1) / (x^9+x^6+7*x^3-1). - _Colin Barker_, Sep 17 2013
%t A134720 Select[Join[{0,0,0},LinearRecurrence[{0,1,1},{1,1,1},100]],EvenQ] (* _Harvey P. Dale_, May 11 2011 *)
%t A134720 LinearRecurrence[{0, 0, 7, 0, 0, 1, 0, 0, 1},{0, 0, 0, 2, 2, 4, 12, 16, 28},37] (* _Ray Chandler_, Mar 02 2024 *)
%Y A134720 Cf. A000931, A135619.
%K A134720 easy,nonn,changed
%O A134720 1,4
%A A134720 _Omar E. Pol_, Nov 11 2007
%E A134720 More terms from _Harvey P. Dale_, May 11 2011