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A274896 Number of 4 X n 0..2 arrays with no element equal to any value at offset (0,-1) (-1,-1) or (-2,0) and new values introduced in order 0..2. 1
6, 14, 38, 104, 290, 815, 2291, 6434, 18065, 50729, 142469, 400121, 1123718, 3155882, 8863073, 24891350, 69905726, 196325636, 551367590, 1548479459, 4348802339, 12213324374, 34300315505, 96330172385, 270536931545, 759785117405 (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) = 5*a(n-1) - 9*a(n-2) + 10*a(n-3) - 6*a(n-4) + a(n-5) for n>6.

Empirical g.f.: x*(6 - 16*x + 22*x^2 - 20*x^3 + 8*x^4 - x^5) / ((1 - x)*(1 - 4*x + 5*x^2 - 5*x^3 + x^4)). - Colin Barker, Jan 31 2019

EXAMPLE

Some solutions for n=4:

..0..1..0..2. .0..1..2..0. .0..1..2..1. .0..1..0..2. .0..1..0..1

..2..1..2..1. .0..1..2..0. .1..2..0..1. .2..1..0..1. .1..2..0..1

..1..0..2..1. .1..2..0..1. .1..0..1..2. .2..0..2..1. .2..0..1..2

..0..2..1..0. .1..2..0..1. .2..0..1..0. .1..0..1..0. .2..0..2..0

CROSSREFS

Row 4 of A274895.

Sequence in context: A271459 A271010 A272579 * A134259 A069166 A184393

Adjacent sequences:  A274893 A274894 A274895 * A274897 A274898 A274899

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jul 10 2016

STATUS

approved

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Last modified March 19 17:21 EDT 2019. Contains 321330 sequences. (Running on oeis4.)