A181202 a(n)=0!*1!*2!*3!*(4*n)!*6*n*(n-1) / ((n)!*(n+1)!*(n+2)!*(n+3)!).

0, 168, 16632, 1729728, 199536480, 25241364720, 3445446284280, 500598983364480, 76591644454765440, 12237255920840932800, 2028351316862121451200, 346968438887939861076480, 60995474427232155123331200

Offset: 1

Author

R. H. Hardin Oct 10 2010

Keywords

• nonn

Comments

(Empirical) Number of nX4 matrices containing a defective permutation of 1..4*n in strictly increasing order rowwise and columnwise, with one permutation value omitted and one repeated (see example)

Column 4 of A181204

Examples

			Some solutions for 2X4
..1..3..4..5....1..2..4..5....2..4..5..7....1..2..3..4....1..3..4..6
..2..5..7..8....3..5..7..8....3..6..7..8....4..5..6..8....5..6..7..8
		

Links

• R. H. Hardin, Table of n, a(n) for n=1..50