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A203340 Number of nX2 0..4 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors 1

%I

%S 1,5,25,95,425,2329,12487,64444,337977,1804892,9639699,51382419,

%T 274455029,1469096024,7868330298,42153003025,225933068001,

%U 1211463181206,6497484955682,34854150590549,186995102014521,1003366634580196

%N Number of nX2 0..4 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors

%C Column 2 of A203346

%H R. H. Hardin, <a href="/A203340/b203340.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 15*a(n-1) -95*a(n-2) +395*a(n-3) -1350*a(n-4) +3559*a(n-5) -7390*a(n-6) +14135*a(n-7) -21343*a(n-8) +28527*a(n-9) -37915*a(n-10) +30518*a(n-11) -42342*a(n-12) +18988*a(n-13) -23243*a(n-14) +15396*a(n-15) +7860*a(n-16) +22676*a(n-17) +24262*a(n-18) +22720*a(n-19) +19127*a(n-20) +12868*a(n-21) +7964*a(n-22) +4145*a(n-23) +1861*a(n-24) +726*a(n-25) +227*a(n-26) +58*a(n-27) +11*a(n-28) +a(n-29)

%e Some solutions for n=5

%e ..4..4....1..1....1..1....2..2....4..4....2..2....3..3....1..1....2..2....0..0

%e ..4..4....3..3....1..1....2..2....4..4....2..2....4..4....2..2....2..2....4..4

%e ..3..4....3..3....4..4....0..2....2..1....1..2....4..4....2..2....2..0....4..4

%e ..4..4....0..0....4..4....3..3....2..2....4..4....3..3....0..0....2..2....4..4

%e ..4..4....0..0....0..0....3..3....2..2....4..4....2..2....0..0....2..2....2..2

%K nonn

%O 1,2

%A _R. H. Hardin_ Dec 31 2011

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Last modified May 21 17:51 EDT 2022. Contains 353921 sequences. (Running on oeis4.)