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 A048478 #14 Sep 08 2022 08:44:57 %S A048478 1,8,29,85,225,561,1345,3137,7169,16129,35841,78849,172033,372737, %T A048478 802817,1720321,3670017,7798785,16515073,34865153,73400321,154140673, %U A048478 322961409,675282945,1409286145,2936012801,6106906625,12683575297,26306674689,54492397569 %N A048478 a(n) = T(6,n), array T given by A048472. %C A048478 n-th difference of a(n), a(n-1), ..., a(0) is (7, 14, 21, ...). %H A048478 Vincenzo Librandi, <a href="/A048478/b048478.txt">Table of n, a(n) for n = 0..1000</a> %H A048478 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (5,-8,4). %F A048478 a(n) = 7*n * 2^(n-1) + 1. %F A048478 a(n) = 5*a(n-1)-8*a(n-2)+4*a(n-3) for n>2. G.f.: (1+3*x-3*x^2) / ((1-x)*(1-2*x)^2). - _Colin Barker_, Feb 18 2016 %o A048478 (Magma) [7*n * 2^(n-1) + 1: n in [0..30]]; // _Vincenzo Librandi_, Sep 23 2011 %o A048478 (PARI) Vec((1+3*x-3*x^2)/((1-x)*(1-2*x)^2) + O(x^40)) \\ _Colin Barker_, Feb 18 2016 %K A048478 nonn,easy %O A048478 0,2 %A A048478 _Clark Kimberling_