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 A290442 #9 Aug 05 2017 13:09:25
%S A290442 1,2,8,45,294,2142,16764,138567,1194050,10638056,97383208,911829646,
%T A290442 8702182020,84418698600,830606179680,8274230277615,83330214144930,
%U A290442 847407871749780,8692682350690800,89868901315880610,935699342853054780,9805180025713805460,103353379063190310600,1095295964528435629050
%N A290442 a(n) = Catalan(n-1)*Motzkin(n).
%F A290442 n*(n+2)*a(n) -2*(2*n+1)*(2*n-3)*a(n-1) -12*(2*n-3)*(2*n-5)*a(n-2) =0. - _R. J. Mathar_, Aug 05 2017
%t A290442 motzkin[n_]:=Hypergeometric2F1[(1-n)/2, -n/2, 2, 4]; Table[CatalanNumber[n - 1] motzkin[n], {n, 50}] (* _Indranil Ghosh_, Aug 04 2017 *)
%Y A290442 Cf. A000108, A001006, A151341, A290443.
%K A290442 nonn
%O A290442 1,2
%A A290442 _N. J. A. Sloane_, Aug 04 2017