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 A048476 #13 Sep 08 2022 08:44:57 %S A048476 1,6,21,61,161,401,961,2241,5121,11521,25601,56321,122881,266241, %T A048476 573441,1228801,2621441,5570561,11796481,24903681,52428801,110100481, %U A048476 230686721,482344961,1006632961,2097152001,4362076161,9059696641,18790481921,38923141121 %N A048476 a(n) = T(4,n), array T given by A048472. %C A048476 n-th difference of a(n), a(n-1), ..., a(0) is (5, 10, 15, ...). %H A048476 Vincenzo Librandi, <a href="/A048476/b048476.txt">Table of n, a(n) for n = 0..1000</a> %H A048476 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (5,-8,4). %F A048476 a(n) = 5*n * 2^(n-1) + 1. %F A048476 a(n) = 5*a(n-1)-8*a(n-2)+4*a(n-3) for n>2. G.f.: (1+x-x^2) / ((1-x)*(1-2*x)^2). - _Colin Barker_, Feb 18 2016 %o A048476 (Magma) [5*n * 2^(n-1) + 1: n in [0..30]]; // _Vincenzo Librandi_, Sep 23 2011 %o A048476 (PARI) Vec((1+x-x^2)/((1-x)*(1-2*x)^2) + O(x^40)) \\ _Colin Barker_, Feb 18 2016 %K A048476 nonn,easy %O A048476 0,2 %A A048476 _Clark Kimberling_