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A198474 Number of 2n X 2 0..2 arrays with values 0..2 introduced in row major order and each element equal to an odd number of horizontal and vertical neighbors. 2
2, 12, 76, 492, 3212, 21036, 137932, 904812, 5936396, 38950572, 255572812, 1676946156, 11003350412, 72199015212, 473737530316, 3108453529452, 20396281280012, 133831275048876, 878140974959692, 5761968373855212 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 1 of A198477.
LINKS
FORMULA
Empirical: a(n) = 9*a(n-1) - 16*a(n-2).
Conjectures from Colin Barker, Mar 02 2018: (Start)
G.f.: 2*x*(1 - 3*x) / (1 - 9*x + 16*x^2).
a(n) = (2^(-4-n)*((9-sqrt(17))^n*(-5+3*sqrt(17)) + (9+sqrt(17))^n*(5+3*sqrt(17)))) / sqrt(17).
(End)
EXAMPLE
Some solutions for n=3:
..0..1....0..0....0..0....0..0....0..1....0..1....0..0....0..1....0..0....0..0
..0..1....1..1....1..1....1..1....0..1....0..1....1..2....0..1....1..1....1..1
..2..2....2..2....0..0....0..0....2..2....2..0....1..2....1..2....2..0....2..2
..1..1....1..1....1..1....2..2....0..0....2..0....0..0....1..2....2..0....0..0
..0..0....2..2....2..2....1..0....1..2....1..1....1..1....0..0....0..2....2..2
..1..1....1..1....0..0....1..0....1..2....2..2....2..2....1..1....0..2....1..1
CROSSREFS
Cf. A198477.
Sequence in context: A052875 A037725 A037620 * A285489 A121680 A277478
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 25 2011
STATUS
approved

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Last modified May 28 00:20 EDT 2024. Contains 372900 sequences. (Running on oeis4.)