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 A026917 #12 Jul 03 2017 11:01:04
%S A026917 1,27,127,399,1039,2439,5383,11439,23743,48567,98455,198495,398863,
%T A026917 799911,1602343,3207567,6418399,12840471,25685047,51374655,102754351,
%U A026917 205514247,411034567,822075759,1644158719,3288325239,6576658903,13153326879,26306663503
%N A026917 a(n) = Sum{T(i,j)}, 0<=j<=i, 0<=i<=n, T given by A026907.
%H A026917 Colin Barker, <a href="/A026917/b026917.txt">Table of n, a(n) for n = 0..1000</a>
%H A026917 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (5,-9,7,-2).
%F A026917 a(n) = 98*2^n - 12*n^2 - 60*n - 97.
%F A026917 From _Colin Barker_, Feb 18 2016: (Start)
%F A026917 a(n) = 5*a(n-1)-9*a(n-2)+7*a(n-3)-2*a(n-4) for n>3.
%F A026917 G.f.: (1+22*x+x^2) / ((1-x)^3*(1-2*x)).
%F A026917 (End)
%t A026917 LinearRecurrence[{5,-9,7,-2},{1,27,127,399},30] (* _Harvey P. Dale_, Jul 03 2017 *)
%o A026917 (PARI) Vec((1+22*x+x^2)/((1-x)^3*(1-2*x)) + O(x^40)) \\ _Colin Barker_, Feb 18 2016
%K A026917 nonn,easy
%O A026917 0,2
%A A026917 _Clark Kimberling_