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A215724
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Maximum absolute value of determinant of n X n (1,-1)-Toeplitz matrix.
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3
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1, 2, 4, 16, 48, 160, 576, 2560, 12288, 73728, 327680, 2097152, 14929920, 68853760, 390905856, 2363752448
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OFFSET
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1,2
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REFERENCES
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Warren D. Smith, Posting to the Math Fun Mailing List, August 18, 2012.
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LINKS
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EXAMPLE
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a(2) = 2:
1 1
-1 1
a(3) = 4:
1 1 1
-1 1 1
1 -1 1
a(6) = 160
1 -1 1 1 1 1
-1 1 -1 1 1 1
-1 -1 1 -1 1 1
-1 -1 -1 1 -1 1
1 -1 -1 -1 1 -1
1 1 -1 -1 -1 1
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MAPLE
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a:=proc(n)
local T, b, U, M, d, r;
T:= combinat:-cartprod([seq({-1, 1}, j = 1..2*n-1)]);
b:= 0;
while not T[finished] do
U := T[nextvalue]();
M := LinearAlgebra:-ToeplitzMatrix(U, n);
d:= abs(LinearAlgebra:-Determinant(M)):
if d > b then b := d; end if;
end do;
return b;
end proc:
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CROSSREFS
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Cf. A086432 (same for circulant (0,1) matrices), A215724 (same for circulant (+1,-1) matrices).
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KEYWORD
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nonn,hard,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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