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 A065731 #23 Dec 13 2024 12:38:46
%S A065731 1,1,1,4,16,100,676,4900,40000,362404,3625216,39904489,478996996,
%T A065731 6226945921,87177877081,1307672296225,20922784184449,355687416544329,
%U A065731 6402373660047556,121645099966283776,2432902006216007824,51090942169052381124,1124000727752683686724
%N A065731 Largest square <= n!.
%H A065731 Harry J. Smith, <a href="/A065731/b065731.txt">Table of n, a(n) for n = 0..100</a>
%F A065731 a(n) = floor(sqrt(n!))^2.
%F A065731 a(n) = A048760(A000142(n)).
%t A065731 Array[Floor@ Sqrt[#!]^2 &, 21, 0] (* _Michael De Vlieger_, Dec 06 2018 *)
%o A065731 (PARI) a(n) = { sqrtint(n!)^2 } \\ _Harry J. Smith_, Oct 28 2009
%o A065731 (Magma) [Floor(Sqrt(Factorial(n)))^2: n in [0..25]]; // _Vincenzo Librandi_, Dec 07 2018
%Y A065731 Cf. A048760, A000142, A065730-A065741.
%K A065731 easy,nonn
%O A065731 0,4
%A A065731 _Labos Elemer_, Nov 15 2001
%E A065731 Offset changed from 1 to 0 by _Harry J. Smith_, Oct 28 2009