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 A256511 #31 Jan 11 2024 16:48:03
%S A256511 1,6,40320,1307674368000,620448401733239439360000,
%T A256511 10333147966386144929666651337523200000000,
%U A256511 12413915592536072670862289047373375038521486354677760000000000
%N A256511 a(n) = (n^2 - 1)!.
%F A256511 a(n) = (2*Pi)^(1/2 - n/2)*n^(n^2 - 1/2)*Product_{j=0..n-1} Gamma(n+j/n). - _Karol A. Penson_, Jan 11 2024
%p A256511 seq(factorial(i^2-1), i = 1 .. 8);
%t A256511 (Range[10]^2-1)! (* _Harvey P. Dale_, Oct 07 2023 *)
%Y A256511 Cf. A000142, A000290, A088020.
%K A256511 nonn
%O A256511 1,2
%A A256511 _Nichole Suomi Smith_, Mar 31 2015