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A275229 Number of 3 X n 0..2 arrays with no element equal to any value at offset (-2,-1) (-2,1) or (-1,0) and new values introduced in order 0..2. 1
2, 11, 61, 339, 1885, 10483, 58301, 324243, 1803293, 10029107, 55777405, 310208979, 1725243613, 9595033459, 53363285309, 296782729491, 1650572823965, 9179747931827, 51053652931069, 283937587062867, 1579133885991517 (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) = 7*a(n-1) - 8*a(n-2).

Conjectures from Colin Barker, Feb 02 2019: (Start)

G.f.: x*(2 - 3*x) / (1 - 7*x + 8*x^2).

a(n) = (2^(-4-n) * ((7-sqrt(17))^n * (-11+3*sqrt(17)) + (7+sqrt(17))^n*(11+3*sqrt(17)))) / sqrt(17).

(End)

EXAMPLE

Some solutions for n=4:

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

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

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

CROSSREFS

Row 3 of A275228.

Sequence in context: A164034 A240548 A255549 * A074615 A126034 A308729

Adjacent sequences:  A275226 A275227 A275228 * A275230 A275231 A275232

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jul 20 2016

STATUS

approved

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Last modified October 22 14:40 EDT 2021. Contains 348170 sequences. (Running on oeis4.)