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 A027086 #27 Sep 08 2022 08:44:49
%S A027086 11,41,108,246,517,1035,2010,3828,7199,13429,24920,46090,85065,156791,
%T A027086 288758,531528,978099,1799521,3310404,6089406,11200845,20602307,
%U A027086 37894354,69699452,128198215,235794285,433694384,797689490,1467180945,2698567791,4963441390
%N A027086 a(n) = A027082(n, n+4).
%H A027086 Colin Barker, <a href="/A027086/b027086.txt">Table of n, a(n) for n = 4..1000</a>
%H A027086 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (4,-5,2,-1,2,-1).
%F A027086 a(n) = A027026(n) + (n+1)(n+2)/2 - 3.
%F A027086 From _Colin Barker_, Feb 20 2016: (Start)
%F A027086 a(n) = 4*a(n-1)-5*a(n-2)+2*a(n-3)-a(n-4)+2*a(n-5)-a(n-6) for n>9.
%F A027086 G.f.: x^4*(11-3*x-x^2-3*x^3+2*x^4) / ((1-x)^3*(1-x-x^2-x^3)).
%F A027086 (End)
%F A027086 a(n) = A000213(n+4) -4 -3*n*(n+3)/2. - _R. J. Mathar_, Jun 24 2020
%t A027086 LinearRecurrence[{4, -5, 2, -1, 2, -1}, {11, 41, 108, 246, 517, 1035}, 35] (* _Vincenzo Librandi_, Feb 20 2016 *)
%o A027086 (PARI) Vec(x^4*(11-3*x-x^2-3*x^3+2*x^4)/((1-x)^3*(1-x-x^2-x^3)) + O(x^40)) \\ _Colin Barker_, Feb 20 2016
%o A027086 (Magma) I:=[11,41,108,246,517,1035]; [n le 6 select I[n] else 4*Self(n-1)-5*Self(n-2)+2*Self(n-3)-Self(n-4)+2*Self(n-5)-Self(n-6): n in [1..40]]; // _Vincenzo Librandi_, Feb 20 2016
%Y A027086 Cf. A027026, A027082.
%K A027086 nonn,easy
%O A027086 4,1
%A A027086 _Clark Kimberling_