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 A048515 #15 Sep 08 2022 08:44:57 %S A048515 1,5,35,160,577,1816,5245,14288,37313,94384,232861,563080,1339249, %T A048515 3141464,7282493,16711456,38010625,85786336,192282301,428342936, %U A048515 948960881,2091908680,4590665245,10032774640,21843934657 %N A048515 a(n) = T(n,n), array T given by A048505. %H A048515 Vincenzo Librandi, <a href="/A048515/b048515.txt">Table of n, a(n) for n = 0..2000</a> %H A048515 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (9,-33,63,-66,36,-8). %F A048515 a(n) = (9*n^2 + n) * 2^(n-2) - n^2 + 1. - _Ralf Stephan_, Feb 05 2004 %F A048515 G.f.: -(8*x^5-43*x^4+53*x^3-23*x^2+4*x-1) / ((x-1)^3*(2*x-1)^3). - _Colin Barker_, Feb 25 2015 %o A048515 (Magma) [(9*n^2 + n) * 2^(n-2) - n^2 + 1: n in [0..30]]; // _Vincenzo Librandi_, Sep 26 2011 %o A048515 (PARI) Vec(-(8*x^5-43*x^4+53*x^3-23*x^2+4*x-1)/((x-1)^3*(2*x-1)^3) + O(x^100)) \\ _Colin Barker_, Feb 25 2015 %K A048515 nonn,easy %O A048515 0,2 %A A048515 _Clark Kimberling_