A223665 Number of nX4 0..1 arrays with rows, diagonals and antidiagonals unimodal.

11, 121, 948, 6454, 44693, 321163, 2343189, 17087771, 124218846, 901767902, 6546694983, 47541956223, 345294309121, 2507850941319, 18213891195978, 132281285512572, 960713718887517, 6977351377339193, 50674293382202763

Offset: 1

Author

R. H. Hardin Mar 25 2013

Keywords

• nonn

Comments

Column 4 of A223669

Examples

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

Links

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

Formula

Empirical: a(n) = 9*a(n-1) -8*a(n-2) -63*a(n-3) +250*a(n-4) -152*a(n-5) -522*a(n-6) -2735*a(n-7) +4120*a(n-8) +9651*a(n-9) +1347*a(n-10) -13682*a(n-11) -24899*a(n-12) +6443*a(n-13) +11258*a(n-14) +8578*a(n-15) -11567*a(n-16) +8480*a(n-17) +22660*a(n-18) -17587*a(n-19) +2236*a(n-20) +4536*a(n-21) -2700*a(n-22) -864*a(n-23)