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A268164 Number of n X 1 0..3 arrays with every repeated value in every row and column one larger mod 4 than the previous repeated value, and upper left element zero. 1
1, 4, 15, 55, 197, 695, 2421, 8351, 28573, 97111, 328197, 1103887, 3697709, 12342407, 41069973, 136292543, 451213885, 1490644663, 4915285029, 16180569199, 53184539981, 174578141159, 572354795445, 1874403215135, 6132368790877 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

FORMULA

Empirical: a(n) = 5*a(n-1) - 2*a(n-2) - 12*a(n-3).

Conjectures from Colin Barker, Jan 11 2019: (Start)

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

a(n) = -3^n + (5/8-11/(8*sqrt(5)))*(1-sqrt(5))^n + (1/40)*(1+sqrt(5))^n*(25+11*sqrt(5)).

(End)

EXAMPLE

Some solutions for n=6:

..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0

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

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

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

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

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

CROSSREFS

Column 1 of A268169.

Sequence in context: A002311 A102349 A219603 * A291029 A126932 A094833

Adjacent sequences:  A268161 A268162 A268163 * A268165 A268166 A268167

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 27 2016

STATUS

approved

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Last modified September 21 05:55 EDT 2020. Contains 337267 sequences. (Running on oeis4.)