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 A064546 #14 Aug 05 2025 21:31:35
%S A064546 0,0,9,64,1900,5184,695310,15089664,346348629,8189440000,170553548176,
%T A064546 4519967588352,202522159449675,8500218417954816,265594041953296875,
%U A064546 3543051899458551808,454740628232312103872,5853583711033675481088,1445271811400044958489895,91546885417441689600000000
%N A064546 Remainder when (n!)^2 is divided by n^n.
%H A064546 Harry J. Smith, <a href="/A064546/b064546.txt">Table of n, a(n) for n = 1..100</a>
%F A064546 a(n) = (n!)^2 mod n^n.
%e A064546 a(5) = 1900 because (5!)^2 = 14400 = 1900 (mod 5^5 = 3125).
%t A064546 A064546[n_] := PowerMod[n!, 2, n^n];
%t A064546 Array[A064546, 20] (* _Paolo Xausa_, Aug 05 2025 *)
%o A064546 (PARI) { for (n=1, 100, write("b064546.txt", n, " ", (n!)^2 % n^n) ) } \\ _Harry J. Smith_, Sep 18 2009
%Y A064546 Cf. A063709, A215460.
%K A064546 nonn
%O A064546 1,3
%A A064546 _Floor van Lamoen_, Oct 09 2001