%I #7 Jul 16 2024 15:30:45
%S 1,1,24,30,56,2160,3960,10192,518400,1211760,3872960,239500800,
%T 668891520,2517424000,181062604800,581935622400,2497284608000,
%U 203152242585600,733238884224000,3511182158848000,316917498433536000,1262637358633728000,6643156644540416000
%N a(n) = (2n)!/(a(n-1)*a(n-2)), where a(0)=1, a(1) = 1.
%F Conjecture D-finite with recurrence a(n) -2*n*(2*n-1)*a(n-3)=0. - _R. J. Mathar_, Jul 16 2024
%t a[0] = 1; a[1] = 1;
%t a[n_] := a[n] = (2n)!/(a[n - 1]*a[n - 2]);
%t Table[a[n], {n, 0, 24}]
%Y Cf. A000142.
%K nonn
%O 0,3
%A _Clark Kimberling_, Jul 15 2024