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A136609
(1/(n!)^2) * number of ways to arrange the consecutive numbers 1...n^2 in an n X n matrix with determinant = 0.
4
0, 0, 76, 14392910
OFFSET
1,3
COMMENTS
The computation of a(5) seems to be currently (Jan 2008) out of reach (compare with A088021(5)).
EXAMPLE
a(1)=0 because det((1))/=0, a(2)=0, because the only possible determinants of a matrix with elements {1,2,3,4} are +-2, +-5 and +-10.
CROSSREFS
Cf. A001044, A046747, a(3)=A088215(0), a(4)=A136608(0), A221976.
Sequence in context: A222739 A060716 A116255 * A116246 A128670 A377337
KEYWORD
hard,more,nonn
AUTHOR
Hugo Pfoertner, Jan 21 2008
STATUS
approved