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A297901 Number of n X 2 0..1 arrays with every element equal to 0, 1, 3 or 4 king-move adjacent elements, with upper left element zero. 6
2, 4, 3, 13, 34, 73, 203, 594, 1443, 4013, 11114, 29073, 79243, 216234, 577883, 1566413, 4247794, 11437273, 30940683, 83723074, 225989523, 610970413, 1651964474, 4462848673, 12062978123, 32607525914, 88115865163, 238159441613 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A297907.

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) + 3*a(n-2) + 8*a(n-3) - 4*a(n-4) - 16*a(n-5) for n>6.

Empirical g.f.: x*(1 + 2*x)*(2 - 2*x - 3*x^2 - 12*x^3 + 12*x^4) / (1 - x - 3*x^2 - 8*x^3 + 4*x^4 + 16*x^5). - Colin Barker, Feb 19 2018

EXAMPLE

Some solutions for n=7:

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

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

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

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

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

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

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

CROSSREFS

Cf. A297907.

Sequence in context: A257503 A091861 A200715 * A079308 A189825 A271878

Adjacent sequences:  A297898 A297899 A297900 * A297902 A297903 A297904

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 08 2018

STATUS

approved

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Last modified December 16 01:43 EST 2019. Contains 330013 sequences. (Running on oeis4.)