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A281465 Number of n X 4 0..1 arrays with no element equal to more than two of its horizontal, diagonal or antidiagonal neighbors and with new values introduced in order 0 sequentially upwards. 1
8, 37, 39, 96, 207, 405, 897, 1975, 4154, 8884, 19297, 41447, 88670, 190913, 411053, 882410, 1895974, 4078246, 8765802, 18835918, 40491783, 87045948, 187087510, 402129300, 864407625, 1858020929, 3993687963, 8584396666, 18452096569 (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) = a(n-1) + a(n-2) + 4*a(n-3) + a(n-4) - 4*a(n-5) - 5*a(n-6) + 3*a(n-8) for n>10.

Empirical g.f.: x*(8 + 29*x - 6*x^2 - 12*x^3 - 84*x^4 - 59*x^5 + 50*x^6 + 90*x^7 + 10*x^8 - 41*x^9) / ((1 - x)*(1 - x^2 - 5*x^3 - 6*x^4 - 2*x^5 + 3*x^6 + 3*x^7)). - Colin Barker, Feb 19 2019

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Column 4 of A281469.

Sequence in context: A050536 A261846 A110215 * A302619 A302411 A303178

Adjacent sequences:  A281462 A281463 A281464 * A281466 A281467 A281468

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 22 2017

STATUS

approved

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Last modified September 29 05:45 EDT 2022. Contains 357082 sequences. (Running on oeis4.)