A067211 Number of n X n 0..3 matrices with all row and column sums equal.

1, 4, 16, 340, 89520, 290838284, 12092687195284, 6675338514190905402, 50327836869668591230004816, 5292118931181847999077738163123240, 7888144623867099277720906683959732404332016, 168815361056027801755263418243053345902341535059333028

Offset: 0

Author

R. H. Hardin, Feb 20 2002

Keywords

• nonn

Examples

			Some solutions for n=3
..2..1..1....1..3..1....0..2..1....2..2..2....0..0..3....1..2..1....1..3..3
..0..1..3....1..1..3....3..0..0....2..2..2....2..1..0....0..1..3....3..1..3
..2..2..0....3..1..1....0..1..2....2..2..2....1..2..0....3..1..0....3..3..1
		

Crossrefs

Column k=3 of A202784.

Extensions

Added one term and example - R. H. Hardin, Jan 05 2012

a(7)-a(10) from Andrew Howroyd, Jun 01 2017

a(11) from Sean A. Irvine, Dec 14 2023

a(0)=1 prepended by Andrew Howroyd, Oct 14 2024