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 A008600 #41 Apr 10 2025 14:10:59
%S A008600 0,18,36,54,72,90,108,126,144,162,180,198,216,234,252,270,288,306,324,
%T A008600 342,360,378,396,414,432,450,468,486,504,522,540,558,576,594,612,630,
%U A008600 648,666,684,702,720,738,756,774,792,810,828,846,864,882,900,918,936
%N A008600 Multiples of 18.
%H A008600 Vincenzo Librandi, <a href="/A008600/b008600.txt">Table of n, a(n) for n = 0..1000</a>
%H A008600 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>.
%H A008600 INRIA Algorithms Project, <a href="http://ecs.inria.fr/services/structure?nbr=330">Encyclopedia of Combinatorial Structures 330</a>.
%H A008600 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1).
%F A008600 G.f.: 18*x/(x-1)^2. - _Vincenzo Librandi_, Jun 10 2013
%F A008600 From _Elmo R. Oliveira_, Apr 10 2025: (Start)
%F A008600 E.g.f.: 18*x*exp(x).
%F A008600 a(n) = 18*n = 2*A008591(n) = A044102(n)/2.
%F A008600 a(n) = 2*a(n-1) - a(n-2). (End)
%t A008600 Range[0, 1000, 18] (* _Vladimir Joseph Stephan Orlovsky_, Jun 01 2011 *)
%t A008600 CoefficientList[Series[18 x / (x - 1)^2, {x, 0, 60}], x] (* _Vincenzo Librandi_, Jun 10 2013 *)
%t A008600 18*Range[0,60] (* _Harvey P. Dale_, Jan 15 2023 *)
%o A008600 (PARI) a(n)=18*n \\ _Charles R Greathouse IV_, Sep 24 2015
%Y A008600 Cf. A008591, A008598, A044102, A154612.
%K A008600 nonn,easy
%O A008600 0,2
%A A008600 _N. J. A. Sloane_