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 A146534 #12 Feb 14 2025 17:29:26
%S A146534 1,8,24,80,280,1008,3696,13728,51480,194480,739024,2821728,10816624,
%T A146534 41602400,160466400,620470080,2404321560,9334424880,36300541200,
%U A146534 141381055200,551386115280,2153031497760,8416395854880,32933722910400,128990414732400,505642425751008,1983674131792416
%N A146534 a(n) = 4*C(2n,n) - 3*0^n.
%F A146534 a(n) = Sum_{k=0..n} A039599(n,k)*A010688(k).
%F A146534 From _Stefano Spezia_, Feb 14 2025: (Start)
%F A146534 G.f.: 4/sqrt(1 - 4*x) - 3.
%F A146534 E.g.f.: 4*exp(2*x)*BesselI(0, 2*x) - 3. (End)
%t A146534 a[n_]:=4*Binomial[2n,n]-3*KroneckerDelta[n,0]; Array[a,27,0] (* _Stefano Spezia_, Feb 14 2025 *)
%Y A146534 Cf. A000984, A010688, A029609, A029651, A039599, A088218, A100320, A144706, A146533, A240530.
%K A146534 nonn
%O A146534 0,2
%A A146534 _Philippe Deléham_, Oct 31 2008
%E A146534 a(22)-a(26) from _Stefano Spezia_, Feb 14 2025