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 A208983 #11 Feb 03 2018 09:55:53
%S A208983 1,2,3,14,20,110,154,910,1260,7752,10659,67298,92092,592020,807300,
%T A208983 5259150,7152444,47071640,63882940,423830264,574221648,3834669566,
%U A208983 5188082354,34834267234,47073334100,317506779800,428634152730,2902365981900,3914819231400
%N A208983 Central terms of the triangle in A208101.
%C A208983 a(2*n+1) = A126596(n).
%H A208983 Reinhard Zumkeller, <a href="/A208983/b208983.txt">Table of n, a(n) for n = 0..1000</a>
%t A208983 T[_, 0] = 1; T[n_, 1] := n; T[n_, n_] := T[n - 1, n - 2]; T[n_, k_] /; 1 < k < n := T[n, k] = T[n - 1, k] + T[n - 1, k - 2];
%t A208983 a[n_] := T[2n, n];
%t A208983 Table[a[n], {n, 0, 30}] (* _Jean-François Alcover_, Feb 03 2018, from A208101 *)
%o A208983 (Haskell)
%o A208983 a208983 n = a208101 (2 * n) n
%K A208983 nonn
%O A208983 0,2
%A A208983 _Reinhard Zumkeller_, Mar 04 2012