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A267912 Number of 1 X n 0..2 arrays with every repeated value in every row unequal to the previous repeated value, and in every column equal to the previous repeated value, and new values introduced in row-major sequential order. 3
1, 2, 4, 11, 29, 77, 201, 525, 1361, 3525, 9097, 23453, 60353, 155189, 398649, 1023501, 2626289, 6736677, 17274601, 44286845, 113516321, 290925845, 745515417, 1910267373, 4894426193, 12539689989, 32125783369, 82301320541, 210838008449 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Row 1 of A267911.

LINKS

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

FORMULA

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

Conjectures from Colin Barker, Feb 25 2018: (Start)

G.f.: x*(1 - x - 4*x^2 + 3*x^3 + 4*x^4) / ((1 - 2*x)*(1 - x - 4*x^2)).

a(n) = (1/17)*2^(-5-n)*(-17*4^(1+n) + (85-19*sqrt(17))*(1-sqrt(17))^n + (1+sqrt(17))^n*(85+19*sqrt(17))) for n>2.

(End)

EXAMPLE

Some solutions for n=8:

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

CROSSREFS

Cf. A267911.

Sequence in context: A148139 A061860 A093960 * A118311 A132836 A148140

Adjacent sequences:  A267909 A267910 A267911 * A267913 A267914 A267915

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 22 2016

STATUS

approved

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Last modified August 4 19:15 EDT 2020. Contains 336202 sequences. (Running on oeis4.)