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A198535 Number of 2n X 2 0..4 arrays with values 0..4 introduced in row major order and each element equal to an even number of horizontal and vertical neighbors. 1
5, 404, 67442, 11739910, 2048681430, 357559607382, 62405998006614, 10891920070833494, 1901001993638057302, 331788019307198829910, 57908034887329483937110, 10106876407223511717074262 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A198538.

LINKS

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

FORMULA

Empirical: a(n) = 189*a(n-1) -2572*a(n-2) +8272*a(n-3) -9984*a(n-4) +4096*a(n-5) for n>6.

Empirical g.f.: x*(5 - 541*x + 3946*x^2 - 8900*x^3 + 7296*x^4 - 1536*x^5) / ((1 - x)*(1 - 12*x + 16*x^2)*(1 - 176*x + 256*x^2)). - Colin Barker, May 14 2018

EXAMPLE

Some solutions for n=3:

..0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1

..1..2....2..3....2..0....2..3....1..0....2..0....2..0....1..2....2..0....1..0

..0..3....3..4....1..3....0..2....2..3....0..3....1..3....0..3....3..2....0..1

..2..0....4..3....4..1....1..0....1..4....1..2....4..1....4..1....4..1....1..0

..0..3....1..4....1..2....4..4....3..3....3..0....0..3....0..2....1..3....2..3

..2..0....4..1....4..0....4..4....3..3....0..1....2..1....3..0....3..4....1..4

CROSSREFS

Cf. A198538.

Sequence in context: A195502 A189307 A198538 * A128866 A221047 A075769

Adjacent sequences:  A198532 A198533 A198534 * A198536 A198537 A198538

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 26 2011

STATUS

approved

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Last modified August 7 22:44 EDT 2020. Contains 336279 sequences. (Running on oeis4.)