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 A168461 #23 Mar 02 2024 13:51:59
%S A168461 0,10,10,20,20,30,30,40,40,50,50,60,60,70,70,80,80,90,90,100,100,110,
%T A168461 110,120,120,130,130,140,140,150,150,160,160,170,170,180,180,190,190,
%U A168461 200,200,210,210,220,220,230,230,240,240,250,250,260,260,270,270,280
%N A168461 a(n) = 10*floor(n/2).
%H A168461 Vincenzo Librandi, <a href="/A168461/b168461.txt">Table of n, a(n) for n = 1..1000</a>
%H A168461 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (1,1,-1).
%F A168461 a(n) = 10*n - a(n-1) - 10, with n>1, a(1)=0.
%F A168461 a(n) = 10*floor(n/2) = A168437(n) - 3. - _Rick L. Shepherd_, Jun 17 2010
%F A168461 G.f.: 10*x^2/((1+x)*(x-1)^2). - _Vincenzo Librandi_, Sep 19 2013
%F A168461 a(n) = a(n-1) +a(n-2) -a(n-3). - _Vincenzo Librandi_, Sep 19 2013
%F A168461 From _G. C. Greubel_, Jul 23 2016: (Start)
%F A168461 a(n) = (5/2)*(2*n + (-1)^n - 1).
%F A168461 E.g.f.: (5/2)*(1 +(2*x - 1)*exp(2*x))*exp(-x). (End)
%p A168461 A168461:=n->10*floor(n/2); seq(A168461(n), n=1..100); # _Wesley Ivan Hurt_, Nov 25 2013
%t A168461 Table[10 Floor[n/2], {n, 70}] (* or *) CoefficientList[Series[10 x/((1 + x) (x - 1)^2), {x, 0, 70}], x] (* _Vincenzo Librandi_, Sep 19 2013 *)
%t A168461 LinearRecurrence[{1,1,-1},{0,10,10},60] (* _Harvey P. Dale_, Mar 02 2024 *)
%o A168461 (Magma) [10*Floor(n/2): n in [1..70]]; // _Vincenzo Librandi_, Sep 19 2013
%Y A168461 Bisections are A008592 and (A008592 MINUS {0}). - _Rick L. Shepherd_, Jun 17 2010
%K A168461 nonn,easy
%O A168461 1,2
%A A168461 _Vincenzo Librandi_, Nov 26 2009
%E A168461 Edited by _Rick L. Shepherd_, Jun 17 2010
%E A168461 Definition rewritten, using Shepherd's formula, by _Vincenzo Librandi_, Sep 19 2013