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 A026915 #9 Feb 18 2016 09:57:28 %S A026915 1,26,100,272,640,1400,2944,6056,12304,24824,49888,100040,200368, %T A026915 401048,802432,1605224,3210832,6422072,12844576,25689608,51379696, %U A026915 102759896,205520320,411041192,822082960,1644166520,3288333664,6576667976,13153336624,26306673944 %N A026915 a(n) = T(n,0) + T(n,1) + ... + T(n,n), T given by A026907. %H A026915 Colin Barker, <a href="/A026915/b026915.txt">Table of n, a(n) for n = 0..1000</a> %H A026915 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (4,-5,2). %F A026915 a(n) = 49*2^n - 24*n - 48. %F A026915 a(n) = 4*a(n-1)-5*a(n-2)+2*a(n-3) for n>2. G.f.: (1+22*x+x^2) / ((1-x)^2*(1-2*x)). - _Colin Barker_, Feb 18 2016 %o A026915 (PARI) Vec((1+22*x+x^2)/((1-x)^2*(1-2*x)) + O(x^40)) \\ _Colin Barker_, Feb 18 2016 %K A026915 nonn,easy %O A026915 0,2 %A A026915 _Clark Kimberling_