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A210286 Number of 2 X 2 matrices with all elements in {0,1,...,n} and determinant = trace.

%I A210286 #7 Nov 26 2016 11:32:43
%S A210286 1,3,10,18,28,42,56,74,96,118,140,170,200,234,272,302,336,386,432,482,
%T A210286 536,578,624,690,752,810,876,938,1000,1082,1156,1234,1328,1402,1476,
%U A210286 1558,1632,1730,1840,1926,2008,2122,2228,2338,2464,2554
%N A210286 Number of 2 X 2 matrices with all elements in {0,1,...,n} and determinant = trace.
%C A210286 See A210000 for a guide to related sequences.
%H A210286 Chai Wah Wu, <a href="/A210286/b210286.txt">Table of n, a(n) for n = 0..10000</a>
%t A210286 a = 0; b = n; z1 = 45;
%t A210286 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 A210286 c[n_, k_] := c[n, k] = Count[t[n], k]
%t A210286 Table[c[n, 0], {n, 0, z1}]    (* A210286 *)
%Y A210286 Cf. A210000.
%K A210286 nonn
%O A210286 0,2
%A A210286 _Clark Kimberling_, Mar 19 2012