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A203184 Number of nX1 0..4 arrays with every nonzero element less than or equal to some horizontal or vertical neighbor 1
1, 5, 25, 95, 325, 1121, 3985, 14288, 50995, 181336, 644721, 2294193, 8166441, 29066618, 103444256, 368138471, 1310164527, 4662787112, 16594519920, 59058487061, 210183969235, 748026706926, 2662163892493, 9474416502527 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 1 of A203191

LINKS

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

FORMULA

Empirical: a(n) = 5*a(n-1) -10*a(n-2) +20*a(n-3) -15*a(n-4) +21*a(n-5) -7*a(n-6) +8*a(n-7) -a(n-8) +a(n-9).

Empirical g.f.: -x*(1+x^2)*(x^6+6*x^4+9*x^2+1) / ( -1+5*x-10*x^2+20*x^3-15*x^4+21*x^5-7*x^6+8*x^7-x^8+x^9 ). - R. J. Mathar, Jul 02 2013

EXAMPLE

Some solutions for n=4

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

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

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

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

CROSSREFS

Sequence in context: A225011 A228457 A213293 * A073374 A126878 A203340

Adjacent sequences:  A203181 A203182 A203183 * A203185 A203186 A203187

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 30 2011

STATUS

approved

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Last modified February 22 18:24 EST 2020. Contains 332148 sequences. (Running on oeis4.)