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 A135322 #21 Apr 03 2021 22:02:17
%S A135322 1,1,2,2,2,12,12,24,90,20,4,168,28,1400,5400,720,90,5940,23100,46200,
%T A135322 180180,17160,1560,140400,11700,45864,179928,13328,52360,5969040,
%U A135322 397936,795872,3133746,12345060,726180,2863224,159068,318136,1255800,4958800
%N A135322 a(n) = gcd(n!, binomial(2n,n)).
%H A135322 G. C. Greubel, <a href="/A135322/b135322.txt">Table of n, a(n) for n = 0..1000</a>
%e A135322 a(5) = 12 as gcd(5!, binomial(2*5, 5)) = gcd(120, 252) = 12. - _David A. Corneth_, Apr 03 2021
%t A135322 Table[GCD[n!, Binomial[2n, n]], {n, 0, 60}] (* _Stefan Steinerberger_, Dec 07 2007 *)
%o A135322 (PARI) valp(n,p)=my(s); while(n\=p, s+=n); s
%o A135322 a(n)=my(s=1,t); forprime(p=2,n, t=valp(n,p); t=min(t,valp(2*n,p)-2*t); if(t, s*=p^t)); s \\ _Charles R Greathouse IV_, Oct 09 2016
%Y A135322 Cf. A000984, A263931.
%K A135322 nonn
%O A135322 0,3
%A A135322 _Leroy Quet_, Dec 06 2007
%E A135322 More terms from _Stefan Steinerberger_, Dec 07 2007