

A231134


Number of (n+1) X (2+1) blacksquare subarrays of 0..2 arrays with no element equal to a strict majority of its diagonal and antidiagonal neighbors, with values 0..2 introduced in row major order.


1



2, 9, 40, 182, 808, 3688, 16368, 74728, 331648, 1514160, 6719936, 30680320, 136161152, 621652928, 2758934016, 12596099456, 55902265856, 255225567744, 1132706802688, 5171449356800, 22951211032576, 104785303002112
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OFFSET

1,1


LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210


FORMULA

Empirical: a(n) = 22*a(n2)  36*a(n4) + 16*a(n6).
Empirical g.f.: x*(2 + 9*x  4*x^2  16*x^3 + 8*x^5) / (1  22*x^2 + 36*x^4  16*x^6).  Colin Barker, Sep 26 2018


EXAMPLE

Some solutions for n=5:
..x..0..x....x..0..x....x..0..x....x..0..x....x..0..x....x..0..x....x..0..x
..1..x..2....1..x..0....1..x..2....1..x..1....0..x..1....0..x..1....1..x..2
..x..1..x....x..2..x....x..1..x....x..2..x....x..1..x....x..2..x....x..0..x
..0..x..0....0..x..0....0..x..1....1..x..1....2..x..0....2..x..0....1..x..2
..x..1..x....x..2..x....x..0..x....x..2..x....x..2..x....x..1..x....x..0..x
..2..x..0....1..x..0....2..x..2....0..x..0....0..x..0....2..x..0....2..x..2


CROSSREFS

Column 2 of A231137.
Sequence in context: A020728 A107979 A021001 * A038112 A268039 A235596
Adjacent sequences: A231131 A231132 A231133 * A231135 A231136 A231137


KEYWORD

nonn


AUTHOR

R. H. Hardin, Nov 04 2013


STATUS

approved



