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 A134987 #15 Oct 18 2022 15:16:38
%S A134987 0,0,0,0,1,4,10,20,35,58,100,192,405,880,1874,3844,7631,14886,29020,
%T A134987 57192,114249,230300,465226,936948,1877771,3748498,7470532,14895728,
%U A134987 29749837,59514152,119166962,238627620,477606935,955315390,1909991772,3818208792
%N A134987 Third extended Jacobsthal recurrence: a(n)=4a(n-1)-6(n-2)+4a(n-3)-a(n-4)+2a(n-5).
%C A134987 See A134658. Sequence is identical to half its fourth differences from second term.
%H A134987 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (4, -6, 4, -1, 2).
%F A134987 O.g.f.: -1/[9(2x-1)]+(-4x^3-2x^2-1)/[9(x^4+2x^2-2x+1)]. - _R. J. Mathar_, Feb 06 2008
%t A134987 LinearRecurrence[{4,-6,4,-1,2},{0,0,0,0,1},60] (* _Harvey P. Dale_, Jul 12 2011 *)
%K A134987 nonn,easy
%O A134987 0,6
%A A134987 _Paul Curtz_, Feb 05 2008
%E A134987 More terms from _Harvey P. Dale_, Jul 12 2011