OFFSET
4,1
FORMULA
An optimal choice and arrangement is of the following form: det((-n, 1-n, n-4), (n-3, 3-n, n), (2-n, n-1, n-2))=2*(2*n^3-7*n^2+6*n+3). There are 35 other equivalent arrangements corresponding to permutations of rows and columns.
G.f.: 2*x^4*(43-64*x+45*x^2-12*x^3)/(1-x)^4. [Colin Barker, Mar 29 2012]
EXAMPLE
Example:a(5)=216 because no larger determinant of a 3 X 3 integer matrix b(j,k) with distinct elements -5<=b(j,k)<=5,j=1..3,k=1..3 can be built than
det((-5,-4,1),(2,-2,5),(-3,4,3))=216.
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Hugo Pfoertner, Aug 24 2004
STATUS
approved