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A266096
Number of n X 3 integer arrays with each element equal to the number of horizontal and antidiagonal neighbors exactly one smaller than itself.
1
4, 13, 64, 230, 1012, 3928, 16428, 65736, 269908, 1091720, 4454304, 18082796, 73622676, 299247292, 1217498296, 4950677020, 20137255328, 81894658192, 333086633092, 1354665687204, 5509630157292, 22408041160240, 91136102570276
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = a(n-1) + 12*a(n-2) + 5*a(n-3) - 12*a(n-4) - 2*a(n-5).
Empirical g.f.: x*(4 + 9*x + 3*x^2 - 10*x^3 - 3*x^4) / (1 - x - 12*x^2 - 5*x^3 + 12*x^4 + 2*x^5). - Colin Barker, Jan 09 2019
EXAMPLE
Some solutions for n=4:
..0..0..1....0..0..0....0..0..0....1..0..0....1..0..0....0..0..0....1..0..0
..1..1..2....1..2..0....1..2..1....0..2..1....1..1..1....0..2..1....0..0..0
..0..1..1....1..0..0....0..0..0....1..0..1....1..0..0....1..0..0....1..2..1
..1..0..0....0..0..1....0..0..0....1..1..0....0..0..0....0..0..1....0..0..1
CROSSREFS
Column 3 of A266101.
Sequence in context: A213093 A135312 A287145 * A005035 A340452 A222771
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 21 2015
STATUS
approved