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A210284 Number of 2 X 2 matrices with all elements in {0,1,...,n} and determinant n+1.

%I A210284 #9 Nov 25 2016 12:21:49
%S A210284 0,0,1,11,9,42,23,81,72,126,79,273,121,268,280,416,227,624,299,761,
%T A210284 570,690,457,1384,672,1004,982,1489,769,2108,893,1980,1500,1768,1574,
%U A210284 3308,1303,2250,2118,3658,1637,4120,1823,3751,3527,3320
%N A210284 Number of 2 X 2 matrices with all elements in {0,1,...,n} and determinant n+1.
%C A210284 See A210000 for a guide to related sequences.
%H A210284 Chai Wah Wu, <a href="/A210284/b210284.txt">Table of n, a(n) for n = 0..3000</a>
%t A210284 a = 0; b = n; z1 = 45;
%t A210284 t[n_] := t[n] = Flatten[Table[w*z - x*y, {w, a, b}, {x, a, b}, {y, a, b}, {z, a, b}]]
%t A210284 c[n_, k_] := c[n, k] = Count[t[n], k]
%t A210284 Table[c[n, n + 1], {n, 0, z1}]   (* A210284 *)
%Y A210284 Cf. A210000.
%K A210284 nonn
%O A210284 0,4
%A A210284 _Clark Kimberling_, Mar 19 2012