A208559 - OEIS

A208559

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

20, 400, 1260, 11020, 52000, 351140, 1913940, 11836400, 67894220, 407225740, 2378376000, 14112662980, 82952260180, 490344818000, 2888730695340, 17052623706380, 100542287612000, 593228737061860, 3498693917381460

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Row 7 of A208555.

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) + 31*a(n-2) + 12*a(n-3) - 144*a(n-4).

Empirical g.f.: 20*x*(1 + 19*x + 12*x^2 - 144*x^3) / (1 - x - 31*x^2 - 12*x^3 + 144*x^4). - Colin Barker, Jul 05 2018

EXAMPLE

Some solutions for n=4:

..0..1..0..0....0..1..1..1....0..1..0..1....0..1..0..1....1..1..0..1

..1..1..0..1....1..0..1..0....0..1..0..0....0..1..1..0....1..0..1..1

..0..1..0..0....0..1..1..1....0..1..0..0....0..1..0..0....1..1..0..0

..0..1..0..0....1..0..1..0....0..1..0..0....0..1..1..0....1..0..1..1

..0..1..0..0....0..1..1..1....0..1..0..0....0..1..0..0....0..1..0..0

..0..1..0..0....1..0..1..0....0..1..0..0....0..1..1..0....1..0..1..1

..0..1..0..0....0..1..0..0....0..1..0..0....0..1..0..0....0..1..0..0

CROSSREFS

Cf. A208555.

Sequence in context: A208122 A207372 A208017 * A209080 A090051 A089957

Adjacent sequences: A208556 A208557 A208558 * A208560 A208561 A208562

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 28 2012

STATUS

approved