A207390 Number of n X 7 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 0 1 and 1 1 0 vertically.

31, 961, 6115, 23071, 65955, 158217, 335915, 651531, 1178343, 2015377, 3292963, 5178919, 7885387, 11676345, 16875819, 23876819, 33151023, 45259233, 60862627, 80734831, 105774835, 137020777, 175664619, 223067739, 280777463, 350544561

Offset

1,1

Comments

Column 7 of A207391.

Links

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

Formula

Empirical: a(n) = (1/210)*n^7 + (103/180)*n^6 + (197/20)*n^5 + (1439/36)*n^4 + (293/20)*n^3 - (3469/90)*n^2 + (157/105)*n + 3.

Conjectures from Colin Barker, Jun 22 2018: (Start)

G.f.: x*(31 + 713*x - 705*x^2 - 677*x^3 + 961*x^4 - 341*x^5 + 45*x^6 - 3*x^7) / (1 - x)^8.

a(n) = 8*a(n-1) - 28*a(n-2) + 56*a(n-3) - 70*a(n-4) + 56*a(n-5) - 28*a(n-6) + 8*a(n-7) - a(n-8) for n>8.

(End)

Example

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

Crossrefs

Cf. A207391.

Sequence in context: A207563 A207418 A223393 * A207518 A207067 A207122

Adjacent sequences: A207387 A207388 A207389 * A207391 A207392 A207393

Keyword

nonn

Author

R. H. Hardin, Feb 17 2012

Status

approved