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A266007 Number of n X 3 integer arrays with each element equal to the number of horizontal and antidiagonal neighbors equal to itself. 1
2, 2, 6, 14, 22, 46, 102, 190, 374, 782, 1542, 3038, 6166, 12334, 24486, 49150, 98486, 196430, 393030, 786974, 1572694, 3144814, 6292710, 12583486, 25162742, 50333582, 100667526, 201318494, 402652822, 805322926, 1610596902, 3221208190 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = a(n-1) + 4*a(n-3).
Empirical g.f.: 2*x*(1 + 2*x^2) / ((1 - 2*x)*(1 + x + 2*x^2)). - Colin Barker, Jan 09 2019
EXAMPLE
Some solutions for n=4:
..1..1..0....0..1..0....1..1..0....1..1..0....0..1..1....0..2..2....0..1..0
..0..2..2....1..2..2....0..1..0....0..2..2....0..2..2....2..2..1....1..2..2
..2..2..1....2..2..0....1..2..2....2..2..0....2..2..1....0..1..0....2..2..0
..0..1..0....1..1..0....2..2..0....1..1..0....0..1..0....0..1..1....0..1..1
CROSSREFS
Column 3 of A266012.
Sequence in context: A233230 A320070 A319866 * A051890 A071109 A005310
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 20 2015
STATUS
approved

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Last modified May 23 11:57 EDT 2024. Contains 372763 sequences. (Running on oeis4.)