A229871 Number of 4X4 0..n arrays with corresponding row and column sums equal.

2432, 384183, 15106048, 266515625, 2805425280, 20610104767, 116211580928, 535021318017, 2098414000000, 7227967108439, 22362655260672, 63219695614153, 165498794685056, 405459218109375, 937601561264128, 2060839403682497

Offset: 1

Author

R. H. Hardin, Oct 01 2013

Keywords

• nonn

Comments

Row 4 of A229870

Examples

			Some solutions for n=4
..0..0..0..0....0..0..0..1....0..0..0..1....0..0..1..1....0..0..1..1
..0..1..2..3....0..0..4..2....0..1..1..3....0..1..2..1....0..1..0..2
..0..4..0..0....1..4..0..1....1..4..2..0....1..3..4..3....1..2..0..0
..0..1..2..3....0..2..2..3....0..0..4..3....1..0..4..1....1..0..2..0
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..73

Formula

Empirical: a(n) = (29/140)*n^13 + (377/140)*n^12 + (3449/210)*n^11 + (13057/210)*n^10 + (34249/210)*n^9 + (21941/70)*n^8 + (6826/15)*n^7 + (53206/105)*n^6 + (60773/140)*n^5 + (119003/420)*n^4 + (28807/210)*n^3 + (9791/210)*n^2 + (348/35)*n + 1