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 A195857 #16 Sep 08 2022 08:45:59 %S A195857 1,11,32,76,168,360,760,1592,3320,6904,14328,29688,61432,126968, %T A195857 262136,540664,1114104,2293752,4718584,9699320,19922936,40894456, %U A195857 83886072,171966456,352321528,721420280,1476395000,3019898872,6174015480,12616466424,25769803768 %N A195857 a(n) = T(9, n), array T given by A047858. %H A195857 Vincenzo Librandi, <a href="/A195857/b195857.txt">Table of n, a(n) for n = 0..3000</a> %H A195857 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (5,-8,4). %F A195857 a(n) = 2^(n-1)*(n+18)-8. %F A195857 a(0)=1, a(1)=11, a(2)=32, a(n) = 5*a(n-1)-8*a(n-2)+4*a(n-3). %F A195857 G.f.: (1+6*x-15*x^2) / ((1-x)*(1-2*x)^2). - _Colin Barker_, Aug 24 2016 %o A195857 (Magma) [2^(n-1)*(n+18)-8: n in [0..30]] %o A195857 (PARI) Vec((1+6*x-15*x^2)/((1-x)*(1-2*x)^2) + O(x^40)) \\ _Colin Barker_, Aug 24 2016 %K A195857 nonn,easy %O A195857 0,2 %A A195857 _Vincenzo Librandi_, Sep 28 2011