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A211141 Number of 2 X 2 matrices having all terms in {-n,...,0,...,n} and determinant n-1.

%I A211141 #10 Jul 16 2017 11:21:23
%S A211141 0,33,52,156,240,492,472,1072,832,1612,1540,2408,1680,4144,2296,4064,
%T A211141 4352,5900,3592,8236,4464,9544,7712,9168,6208,15984,8812,12232,11968,
%U A211141 17504,9464,23712,10976,21772,17440,19960
%N A211141 Number of 2 X 2 matrices having all terms in {-n,...,0,...,n} and determinant n-1.
%C A211141 For a guide to related sequences, see A210000.
%H A211141 Chai Wah Wu, <a href="/A211141/b211141.txt">Table of n, a(n) for n = 0..3000</a>
%t A211141 a = -n; b = n; z1 = 35;
%t A211141 t[n_] := t[n] = Flatten[Table[w*z - x*y, {w, a, b}, {x, a, b}, {y, a, b}, {z, a, b}]]
%t A211141 c[n_, k_] := c[n, k] = Count[t[n], k]
%t A211141 Table[c[n, n - 1], {n, 0, z1}]  (* A211141 *)
%Y A211141 Cf. A210000.
%K A211141 nonn
%O A211141 0,2
%A A211141 _Clark Kimberling_, Apr 02 2012