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 A064363 #6 Nov 26 2013 10:32:34
%S A064363 0,2,14,51,133,289,547,954,1546,2380,3508,5005,6915,9347,12353,16028,
%T A064363 20468,25790,32054,39427,47965,57833,69155,82082,96682,113192,131720,
%U A064363 152429,175467,201075,229305,260492,294700,332182,373138,417751,466201
%N A064363 Number of 2 X 2 regular integer matrices with elements from {0,...,n} up to row and column permutation.
%F A064363 a(n) = ((n+1)*(n^3+3*n^2+4*n+1)-A059306(n))/4.
%e A064363 There are 2 binary regular matrices up to row and column permutation:
%e A064363 [1 0] [1 1]
%e A064363 [0 1] [1 0].
%t A064363 A059306[0] = 1; A059306[n_] := Table[{w, x, y, z} /. {ToRules[ Reduce[0 <= x <= n && 0 <= y <= n && 0 <= z <= n && w*z - x*y == 0, {x, y, z}, Integers]]}, {w, 0, n}] // Flatten[#, 1] & // Length; a[n_] := ((n + 1)*(n^3 + 3*n^2 + 4*n + 1) - A059306[n])/4; Table[Print[an = a[n]]; an, {n, 0, 36}] (* _Jean-François Alcover_, Nov 26 2013 *)
%Y A064363 Cf. A064276, A059306, A062801, A059976, A039623.
%K A064363 nonn,nice,easy
%O A064363 0,2
%A A064363 _Vladeta Jovovic_, Sep 25 2001