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 A113436 #11 Jul 09 2024 22:21:00
%S A113436 1,2,7,26,98,371,1406,5329,20196,76532,289997,1098826,4163483,
%T A113436 15775426,59772826,226477879,858118966,3251390237,12319431012,
%U A113436 46677994276,176861668393,670124115506,2539082288671,9620514646154,36451871795186
%N A113436 First row of A113435.
%H A113436 G. C. Greubel, <a href="/A113436/b113436.txt">Table of n, a(n) for n = 0..1000</a>
%H A113436 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (7,-15,11,-1).
%F A113436 a(n) = A113435(3*n).
%F A113436 a(n) = 7*a(n-1) - 15*a(n-2) + 11*a(n-3) - a(n-4).
%F A113436 G.f.: (1 -5*x +8*x^2 -4*x^3)/(1 -7*x +15*x^2 -11*x^3 +x^4).
%t A113436 CoefficientList[Series[(1 - 5*x + 8*x^2 - 4*x^3)/(1 - 7*x + 15*x^2 - 11*x^3 + x^4), {x,0,50}], x] (* or *) LinearRecurrence[{7,-15,11,-1}, {1, 2,7,26}, 50] (* _G. C. Greubel_, Mar 10 2017 *)
%o A113436 (PARI) my(x='x+ O(x^50)); Vec((1 -5*x +8*x^2 -4*x^3)/(1 -7*x +15*x^2 -11*x^3 +x^4)) \\ _G. C. Greubel_, Mar 10 2017
%Y A113436 Cf. A113435.
%K A113436 nonn,easy
%O A113436 0,2
%A A113436 _Floor van Lamoen_, Nov 04 2005