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A283692 Number of 2 X n 0..1 arrays with no 1 equal to more than two of its horizontal, diagonal and antidiagonal neighbors. 1
4, 16, 49, 161, 548, 1824, 6081, 20353, 68036, 227376, 760145, 2541153, 8494692, 28397120, 94929633, 317342017, 1060849668, 3546339664, 11855139953, 39630819361, 132482782884, 442879752544, 1480512941569, 4949240890113 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) + a(n-2) + 3*a(n-3) - 6*a(n-4) - 8*a(n-5).

Empirical g.f.: x*(4 + 4*x - 3*x^2 - 14*x^3 - 8*x^4) / ((1 + x + 2*x^2)*(1 - 4*x + x^2 + 4*x^3)). - Colin Barker, Feb 21 2019

EXAMPLE

Some solutions for n=4:

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

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

CROSSREFS

Row 2 of A283691.

Sequence in context: A114185 A188516 A188501 * A173712 A085697 A262268

Adjacent sequences:  A283689 A283690 A283691 * A283693 A283694 A283695

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 14 2017

STATUS

approved

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Last modified May 26 17:16 EDT 2022. Contains 354092 sequences. (Running on oeis4.)