

A197102


Half the number of n X 1 0..3 arrays with no element equal to the average of its horizontal and vertical neighbors.


1



2, 6, 16, 61, 212, 753, 2661, 9415, 33302, 117802, 416703, 1474018, 5214089, 18443961, 65242401, 230783990, 816359440, 2887733833, 10214871388, 36133384697, 127815754113, 452126672783, 1599321849338, 5657331300590
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OFFSET

1,1


COMMENTS

Column 1 of A197109.


LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200


FORMULA

Empirical: a(n) = 2*a(n1) +5*a(n2) +3*a(n3) 4*a(n4) 4*a(n5) for n>6.
Empirical g.f.: x*(2 + 2*x  6*x^2  7*x^3 + 8*x^5) / (1  2*x  5*x^2  3*x^3 + 4*x^4 + 4*x^5).  Colin Barker, May 11 2018


EXAMPLE

Some solutions for 4 X 4:
..0....0....0....0....1....1....0....1....1....1....1....0....0....0....1....1
..1....1....3....3....0....0....3....3....0....0....2....1....3....1....0....2
..1....0....3....2....3....0....3....0....0....1....0....1....0....0....3....0
..0....3....1....0....2....2....2....2....1....0....2....3....1....2....0....1


CROSSREFS

Cf. A197109.
Sequence in context: A027742 A324062 A033301 * A093113 A150030 A150031
Adjacent sequences: A197099 A197100 A197101 * A197103 A197104 A197105


KEYWORD

nonn


AUTHOR

R. H. Hardin, Oct 10 2011


STATUS

approved



