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 A191466 #26 Apr 01 2025 03:28:01
%S A191466 0,4,56,604,5936,55924,515816,4704844,42656096,385467364,3477018776,
%T A191466 31332231484,282185395856,2540645125204,22870688939336,
%U A191466 205860614516524,1852867600961216,16676418760213444,150090820599733496,1350832644186663964,12157570091625288176,109418512294354156084
%N A191466 a(n) = 9^n - 5^n.
%H A191466 Vincenzo Librandi, <a href="/A191466/b191466.txt">Table of n, a(n) for n = 0..300</a>
%H A191466 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (14,-45).
%F A191466 a(n) = 14*a(n-1) - 45*a(n-2).
%F A191466 From _Vincenzo Librandi_, Oct 05 2014: (Start)
%F A191466 G.f.: 4*x/((1-5*x)*(1-9*x)).
%F A191466 a(n+1) = 4*A016163(n). (End)
%F A191466 E.g.f.: 2*exp(14*x/2)*sinh(2*x). - _Elmo R. Oliveira_, Mar 31 2025
%t A191466 Table[9^n - 5^n, {n, 0, 25}] (* or *) CoefficientList[Series[4 x/((1 - 5 x) (1 - 9 x)), {x, 0, 30}], x] (* _Vincenzo Librandi_, Oct 05 2014 *)
%t A191466 LinearRecurrence[{14,-45},{0,4},20] (* _Harvey P. Dale_, Jun 26 2019 *)
%o A191466 (Magma) [9^n-5^n: n in [0..20]];
%o A191466 (PARI) a(n)=9^n-5^n \\ _Charles R Greathouse IV_, Jun 08 2011
%Y A191466 Cf. A016163, A016185, A059410, A118004.
%K A191466 nonn,easy
%O A191466 0,2
%A A191466 _Vincenzo Librandi_, Jun 03 2011