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A211145 Number of 2 X 2 matrices having all terms in {-n,...,0,..,n} and permanent=trace.

%I A211145 #10 Aug 11 2025 19:27:07
%S A211145 1,19,60,116,196,292,404,548,708,868,1060,1284,1524,1796,2052,2292,
%T A211145 2612,2980,3348,3748,4116,4452,4884,5380,5844,6324,6820,7300,7860,
%U A211145 8468,9060,9732,10388,10964,11572,12180,12852,13668,14436,15092
%N A211145 Number of 2 X 2 matrices having all terms in {-n,...,0,..,n} and permanent=trace.
%C A211145 For a guide to related sequences, see A210000.
%H A211145 David Radcliffe, <a href="/A211145/b211145.txt">Table of n, a(n) for n = 0..2000</a>
%t A211145 a = -n; b = n; z1 = 40;
%t A211145 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 A211145 c[n_, k_] := c[n, k] = Count[t[n], k]
%t A211145 Table[c[n, 0], {n, 0, z1}]   (* A211145 *)
%t A211145 (1/4) Table[c[n, n], {n, 2, z1}] (* integers *)
%Y A211145 Cf. A210000.
%K A211145 nonn
%O A211145 0,2
%A A211145 _Clark Kimberling_, Apr 03 2012