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%I #12 May 12 2021 10:13:05
%S 1,3,13,43,129,327,761,1619,3238,6098,10974,18930,31550,50930,80030,
%T 122666,183999,270525,390755,555205,777287,1073297,1463583,1972533,
%U 2630044,3471508,4539660,5884564,7565868,9652788,12226860,15381924
%N Number of nonnegative integer 3 X 3 matrices with sum of elements equal to n, up to rotational symmetry.
%H Andrew Howroyd, <a href="/A054771/b054771.txt">Table of n, a(n) for n = 0..1000</a>
%F G.f.: (x^8 - 2*x^7 + 6*x^6 + 2*x^5 + 2*x^4 + 2*x^3 + 6*x^2 - 2*x + 1)/((1 - x^4)^2*(1 - x^2)^2*(1 - x)^5).
%Y Row n=3 of A343874.
%Y Cf. A008610, A054343.
%K easy,nonn
%O 0,2
%A _Vladeta Jovovic_, May 18 2000
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