A181200 a(n) = 0!*1!*2!*...*(n-1)! *(n^2)! *(n*(n-1))^2 / 2*n!*(n+1)!*...*(2*n-1)!

0, 4, 756, 1729728, 140229804000, 752239365180732000, 419014989521191873479589920, 34623595988556658225393154134784716800, 571228532851873223553288547443139274046846826752000

Offset: 1

Author

R. H. Hardin Oct 10 2010

Keywords

• nonn

Comments

(Empirical) Number of n X n matrices containing a defective permutation of 1..n*n in strictly increasing order rowwise and columnwise, with one permutation value omitted and one repeated (see example)

Diagonal of A181204

Examples

			Some solutions for 3X3
..2..3..5....1..2..5....1..2..6....1..3..4....1..3..4....1..2..4....1..3..5
..4..6..7....3..4..6....3..4..8....2..5..8....2..6..7....2..5..7....2..4..6
..5..8..9....4..7..9....6..7..9....4..6..9....5..7..9....3..6..9....6..7..8
		

Links

• R. H. Hardin, Table of n, a(n) for n=1..22