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 A204041 #6 Mar 30 2012 17:27:26
%S A204041 -4,2560000,-19188605030400000000,
%T A204041 26257841860510325145600000000000000000000,
%U A204041 -50074374492086859469933185828103742596055040000000000000000000000000000
%N A204041 Square Gaussian integer factorial, product of all Gaussian integers except 0 having a real or imaginary part less than or equal to n.
%C A204041 This is called "square" because the Gaussian integers involved here form a square on the complex plane.
%C A204041 All terms are purely real integers, but a(6) has more than a hundred digits.
%e A204041 a(1) = 1 * (1 + i) * i * (-1 + i) * -1 * (-1 - i) * -i * (1 - i) = -4.
%t A204041 Table[Times@@ReplaceAll[Flatten[Table[a + b I, {a, -n, n}, {b, -n, n}]], 0 -> 1], {n, 10}]
%Y A204041 Cf. A204044, lozenge factorial; A204043, circle factorial.
%K A204041 sign
%O A204041 1,1
%A A204041 _Alonso del Arte_, Jan 09 2012