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A281210 Number of 6 X n 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards. 1
0, 420, 1120, 1588, 2602, 4248, 6838, 11010, 17840, 29120, 47838, 78978, 130842, 217250, 361188, 600860, 999718, 1663078, 2765630, 4596962, 7636856, 12679768, 21040526, 34894090, 57836514, 95810754, 158634028, 262516660, 434214550 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

FORMULA

Empirical: a(n) = 4*a(n-1) - 4*a(n-2) - 2*a(n-3) + 4*a(n-4) - a(n-6) for n>12.

Empirical g.f.: 2*x^2*(210 - 280*x - 606*x^2 + 785*x^3 + 376*x^4 - 525*x^5 - 39*x^6 + 180*x^7 + 36*x^8 - 6*x^9 - 3*x^10) / ((1 - x)^2*(1 - x - x^2)^2). - Colin Barker, Feb 18 2019

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

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

CROSSREFS

Row 6 of A281205.

Sequence in context: A169825 A135196 A259025 * A235233 A251084 A250383

Adjacent sequences:  A281207 A281208 A281209 * A281211 A281212 A281213

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 17 2017

STATUS

approved

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Last modified January 25 23:08 EST 2020. Contains 331270 sequences. (Running on oeis4.)