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 A327998 #9 May 11 2022 17:07:33
%S A327998 1,1,4,36,36,900,400,19600,4900,396900,63504,7683984,853776,144288144,
%T A327998 11778624,2650190400,165636900,47869064100,2363904400,853369488400,
%U A327998 34134779536,15053437775376,497634306624,263248548204096,7312459672336,4570287295210000,108172480360000
%N A327998 a(n) = (n!/floor(n/2)!^2)^2.
%F A327998 a(n) = [x^n] (2/(Pi*(1 - 16*x^2)^2))*(2*x*EllipticE(4*x) + (16*x^2 - 1)*(16*x^2 - 1 + x)*EllipticK(4*x)).
%p A327998 seq((n!/iquo(n,2)!^2)^2, n = 0..26); # Or:
%p A327998 gf := (2/(Pi*(1 - 16*x^2)^2))*(2*x*EllipticE(4*x) + (16*x^2 - 1)*(16*x^2 - 1 + x)* EllipticK(4*x)): ser := series(gf, x, 30): seq(coeff(ser, x, n), n = 0..26);
%t A327998 Table[(n!/(Floor[n/2]!)^2)^2,{n,0,30}] (* _Harvey P. Dale_, May 11 2022 *)
%Y A327998 Central column of A328001.
%Y A327998 Even bisection is A002894.
%K A327998 nonn
%O A327998 0,3
%A A327998 _Peter Luschny_, Oct 19 2019