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A198522
Number of n X 2 0..4 arrays with values 0..4 introduced in row major order and each element equal to no more than two horizontal and vertical neighbors.
2
2, 15, 193, 3660, 81844, 1948672, 47436498, 1163606279, 28617909415, 704465305625, 17346617064022, 427184684002131, 10520398796919219, 259092051772297458, 6380839372392481249, 157145577058895542027
OFFSET
1,1
COMMENTS
Column 2 of A198528.
LINKS
FORMULA
Empirical: a(n) = 35*a(n-1) -267*a(n-2) +246*a(n-3) +924*a(n-4) +710*a(n-5) -1736*a(n-6) -1860*a(n-7) +72*a(n-8) +1984*a(n-9) +720*a(n-10) -320*a(n-11) -512*a(n-12) for n > 14.
EXAMPLE
Some solutions for n=4
..0..0....0..1....0..0....0..1....0..1....0..1....0..1....0..0....0..1....0..0
..0..1....2..0....1..0....2..3....2..0....2..0....0..2....0..1....2..3....1..2
..2..3....2..2....2..3....4..2....1..0....0..2....1..3....1..0....1..2....1..3
..2..2....3..1....0..1....0..3....2..1....2..3....0..0....0..0....1..0....1..2
CROSSREFS
Cf. A198528.
Sequence in context: A328121 A374866 A127090 * A187655 A046249 A042355
KEYWORD
nonn
AUTHOR
R. H. Hardin Oct 26 2011
STATUS
approved