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 A054113 #16 May 11 2024 17:14:40
%S A054113 1,5,17,57,197,701,2549,9413,35153,132393,501905,1912769,7321081,
%T A054113 28122281,108355481,418590521,1620751301,6287963741,24438234341,
%U A054113 95128761941,370821819581,1447337568461,5655535495901,22122396951101,86617604317301,339438817192805,1331275883089013
%N A054113 T(2*n,n), array T as in A054110.
%H A054113 Stefano Spezia, <a href="/A054113/b054113.txt">Table of n, a(n) for n = 0..1000</a>
%F A054113 G.f.: (-1+4*x+2*sqrt(1-4*x))/((1-x)*(1-4*x)). - _Ralf Stephan_, Apr 03 2004
%F A054113 a(n) = 4*s(n) + 1, with s(n) = A079309(n) = Sum_{k=1..n} C(2k+1, k+1). - _Ralf Stephan_, Apr 03 2004
%t A054113 CoefficientList[Series[( -1+4x+2*Sqrt[1-4x])/((1-x)(1-4x)),{x,0,26}],x] (* _Stefano Spezia_, May 11 2024 *)
%Y A054113 Cf. A054110, A079309.
%K A054113 nonn
%O A054113 0,2
%A A054113 _Clark Kimberling_