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 A242983 #17 Jul 19 2018 11:14:55
%S A242983 0,1,1,12,58,175,411,826,1492,2493,3925,5896,8526,11947,16303,21750,
%T A242983 28456,36601,46377,57988,71650,87591,106051,127282,151548,179125,
%U A242983 210301,245376,284662,328483,377175,431086,490576,556017
%N A242983 n/2 * (n^3 - 2*n^2 - 2*n + 5).
%C A242983 For n>1, number of ways to place two dominoes horizontally on an n X n chessboard.
%H A242983 <a href="/index/Do#domino">Index entries for sequences related to dominoes</a>
%H A242983 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (5,-10,10,-5,1).
%F A242983 a(n) = A019582(n) + A077414(n-2), n>1.
%F A242983 G.f.: x*(-2*x^3 + 17*x^2 - 4*x + 1) / (1-x)^5.
%t A242983 Table[n/2 (n^3-2n^2-2n+5),{n,0,40}] (* or *) LinearRecurrence[{5,-10,10,-5,1},{0,1,1,12,58},40] (* _Harvey P. Dale_, Jul 19 2018 *)
%Y A242983 Cf. A242856, A242861.
%K A242983 nonn,easy
%O A242983 0,4
%A A242983 _Ralf Stephan_, Jun 09 2014