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A115221 Number of 3 X 3 matrices over Z(n) having determinant 0. 2

%I

%S 1,344,8451,100864,465125,2907144,6569479,27557888,59895369,160003000,

%T 233671691,852401664,878081581,2259900776,3930771375

%N Number of 3 X 3 matrices over Z(n) having determinant 0.

%F a(n)=n^9-A115222(n). For prime n, a(n)=n^3 (n^5+n^4-n^2-n+1)

%t Table[cnt=0; Do[m={{a, b, c}, {d, e, f}, {g, h, i}}; If[Det[m, Modulus->n]==0, cnt++ ], {a, 0, n-1}, {b, 0, n-1}, {c, 0, n-1}, {d, 0, n-1}, {e, 0, n-1}, {f, 0, n-1}, {g, 0, n-1}, {h, 0, n-1}, {i, 0, n-1}]; cnt, {n, 2, 7}]

%K mult,nonn

%O 1,2

%A _T. D. Noe_, Jan 16 2006

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Last modified June 17 14:09 EDT 2019. Contains 324185 sequences. (Running on oeis4.)