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 A027013 #11 Oct 08 2018 19:05:58
%S A027013 1,8,107,654,2801,9859,30869,89951,250780,680665,1818310,4813018,
%T A027013 12674542,33283434,87272241,228658744,598864479,1568137061,4105798635,
%U A027013 10749568905,28143285770,73680744203,192899492252,505018380164,1322156411756,3461451749404
%N A027013 a(n) = T(2*n, n+2), T given by A027011.
%H A027013 Colin Barker, <a href="/A027013/b027013.txt">Table of n, a(n) for n = 2..1000</a>
%H A027013 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (8,-26,45,-45,26,-8,1).
%F A027013 G.f.: x^2*(1+69*x^2-39*x^3+36*x^4-26*x^5+8*x^6-x^7) / ((1-x)^5*(1-3*x+x^2)). - _Colin Barker_, Feb 19 2016
%t A027013 LinearRecurrence[{8,-26,45,-45,26,-8,1},{1,8,107,654,2801,9859,30869,89951},30] (* _Harvey P. Dale_, Oct 08 2018 *)
%o A027013 (PARI) Vec(x^2*(1+69*x^2-39*x^3+36*x^4-26*x^5+8*x^6-x^7)/((1-x)^5*(1-3*x+x^2)) + O(x^40)) \\ _Colin Barker_, Feb 19 2016
%K A027013 nonn,easy
%O A027013 2,2
%A A027013 _Clark Kimberling_