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A184145 1/4 the number of (n+1) X 2 0..3 arrays with every 2 X 2 subblock having at least two equal elements connected horizontally or vertically. 1
43, 499, 5695, 65227, 746503, 8544883, 97806031, 1119511003, 12814167895, 146673819139, 1678861073311, 19216616595691, 219957659413927, 2517684199404691, 28817972258232175, 329856907907420923 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A184153.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = 9*a(n-1) + 28*a(n-2).

Conjectures from Colin Barker, Apr 12 2018: (Start)

G.f.: x*(43 + 112*x) / (1 - 9*x - 28*x^2).

a(n) = (2^(-n)*((9-sqrt(193))^n*(-25+2*sqrt(193)) + (9+sqrt(193))^n*(25+2*sqrt(193)))) / sqrt(193).

(End)

EXAMPLE

Some solutions for 3 X 2 with a(1,1)=0:

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

..3..2....1..1....2..0....1..1....0..2....0..3....1..1....0..0....1..2....0..0

..0..2....2..3....0..0....1..0....3..2....1..1....3..2....0..3....1..2....0..2

CROSSREFS

Cf. A184153.

Sequence in context: A188133 A194784 A184153 * A238202 A008388 A241939

Adjacent sequences:  A184142 A184143 A184144 * A184146 A184147 A184148

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 09 2011

STATUS

approved

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Last modified March 26 20:42 EDT 2019. Contains 321534 sequences. (Running on oeis4.)