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A217450 Number of n X 1 arrays of the minimum value of corresponding elements and their horizontal and vertical neighbors in a random 0..2 n X 1 array. 5
3, 3, 9, 17, 37, 77, 163, 343, 723, 1523, 3209, 6761, 14245, 30013, 63235, 133231, 280707, 591427, 1246089, 2625409, 5531525, 11654477, 24555043, 51735495, 109002515, 229659507, 483874057, 1019483609, 2147969733, 4525598973 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A217457.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) + a(n-4).

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

EXAMPLE

All solutions for n=3:

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

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

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

CROSSREFS

Sequence in context: A285883 A232948 A241357 * A089892 A038221 A099465

Adjacent sequences:  A217447 A217448 A217449 * A217451 A217452 A217453

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 03 2012

STATUS

approved

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Last modified January 26 20:11 EST 2020. Contains 331288 sequences. (Running on oeis4.)