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

1,1

Comments

Column 4 of A223669

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)

Example

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

Crossrefs

Sequence in context: A223640 A223633 A223616 * A068179 A293891 A218262

Adjacent sequences: A223662 A223663 A223664 * A223666 A223667 A223668

Keyword

nonn

Author

R. H. Hardin Mar 25 2013

Status

approved