A224393 Number of 4Xn 0..3 arrays with diagonals and antidiagonals unimodal and rows nondecreasing.

256, 10000, 86701, 497958, 2332222, 9331553, 32806574, 103452812, 297410156, 789731500, 1957606141, 4569537752, 10116846904, 21372349639, 43300242010, 84493906854, 159387825448, 291579791772, 518714491591, 899524090772

Offset: 1

Author

R. H. Hardin Apr 05 2013

Keywords

• nonn

Comments

Row 4 of A224391

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = (3551/47900160)*n^12 + (17561/13305600)*n^11 + (410317/21772800)*n^10 + (127787/725760)*n^9 + (394837/290304)*n^8 + (4724393/1209600)*n^7 + (880093831/21772800)*n^6 - (673403/80640)*n^5 + (476636641/1088640)*n^4 + (58121267/907200)*n^3 - (1924453/415800)*n^2 - (1998055/2772)*n + 1906 for n>4