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 A024496 #18 Mar 12 2019 09:33:57
%S A024496 3,7,33,195,1292,9177,68310,525915,4153380,33460284,273904969,
%T A024496 2271800037,19050406788,161242554550,1375709203260,11819200090635,
%U A024496 102162535941492,887830494976788,7752586858050900,67986848888695660,598522586288243760,5287559893638230385
%N A024496 a(n) = (3/(8n-4))*C(4n,n).
%F A024496 G.f.: (g+2)*(g-1)/g^2 where g = 1+x*g^4 is the g.f. of A002293. - _Mark van Hoeij_, Nov 11 2011
%F A024496 a(n) ~ 2^(8*n - 5/2) / (sqrt(Pi) * n^(3/2) * 3^(3*n - 1/2)). - _Vaclav Kotesovec_, Mar 12 2019
%t A024496 Table[3/(8*n - 4)*Binomial[4*n, n], {n, 1, 20}] (* _Vaclav Kotesovec_, Mar 12 2019 *)
%o A024496 (PARI) a(n) = 3*binomial(4*n, n)/(8*n-4); \\ _Michel Marcus_, Mar 12 2019
%Y A024496 Cf. A005810.
%K A024496 nonn
%O A024496 1,1
%A A024496 _Clark Kimberling_
%E A024496 More terms from _Vaclav Kotesovec_, Mar 12 2019