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 A210288 #7 Dec 08 2016 04:27:39
%S A210288 1,6,19,29,41,51,65,75,89,101,115,125,143,153,167,181,197,207,225,235,
%T A210288 253,267,281,291,313,325,339,353,371,381,403,413,431,445,459,473,497,
%U A210288 507,521,535,557,567,589,599,617,635
%N A210288 Number of 2 X 2 matrices with all elements in {0,1,...,n} and permanent = trace.
%C A210288 See A210000 for a guide to related sequences.
%H A210288 Chai Wah Wu, <a href="/A210288/b210288.txt">Table of n, a(n) for n = 0..10000</a>
%t A210288 a = 0; b = n; z1 = 45;
%t A210288 t[n_] := t[n] = Flatten[Table[w + z - w*z - x*y, {w, a, b}, {x, a, b}, {y, a, b}, {z, a, b}]]
%t A210288 c[n_, k_] := c[n, k] = Count[t[n], k]
%t A210288 Table[c[n, 0], {n, 0, z1}] (* A210288 *)
%Y A210288 Cf. A210000.
%K A210288 nonn
%O A210288 0,2
%A A210288 _Clark Kimberling_, Mar 19 2012