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 A048500 #19 Sep 08 2022 08:44:57 %S A048500 1,2,11,43,135,375,967,2375,5639,13063,29703,66567,147463,323591, %T A048500 704519,1523719,3276807,7012359,14942215,31719431,67108871,141557767, %U A048500 297795591,624951303,1308622855,2734686215,5704253447,11878268935,24696061959,51271172103 %N A048500 a(n) = 2^(n-1)*(7*n-12)+7. %H A048500 Vincenzo Librandi, <a href="/A048500/b048500.txt">Table of n, a(n) for n = 0..1000</a> %H A048500 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (5,-8,4). %F A048500 a(n) = T(6, n), array T given by A048494. %F A048500 a(0)=1, a(1)=2, a(2)=11, a(n) = 5*a(n-1)-8*a(n-2)+4*a(n-3). - _Harvey P. Dale_ and _Vincenzo Librandi_, Sep 23 2011 %F A048500 G.f.: (1-3*x+9*x^2) / ((1-x)*(1-2*x)^2). - _Colin Barker_, Aug 24 2016 %o A048500 (Magma) [2^(n-1)*(7*n-12)+7: n in [0..30]]; // _Vincenzo Librandi_, Sep 23 2011 %o A048500 (PARI) Vec((1-3*x+9*x^2)/((1-x)*(1-2*x)^2) + O(x^40)) \\ _Colin Barker_, Aug 24 2016 %Y A048500 Cf. A048494. %K A048500 nonn,easy %O A048500 0,2 %A A048500 _Clark Kimberling_ %E A048500 Formula from _Ralf Stephan_, Jan 15 2004