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A203332 Number of nX2 0..5 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors 1
1, 6, 36, 161, 846, 5545, 35483, 216488, 1340730, 8480848, 53643799, 338093942, 2134537993, 13508527719, 85530509012, 541535824313, 3429939732074, 21732616374723, 137726568471728, 872907436160530, 5533065935012257 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 2 of A203338

LINKS

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

FORMULA

Empirical: a(n) = 21*a(n-1) -195*a(n-2) +1175*a(n-3) -5545*a(n-4) +21045*a(n-5) -64898*a(n-6) +173439*a(n-7) -400482*a(n-8) +801950*a(n-9) -1477586*a(n-10) +2342826*a(n-11) -3466079*a(n-12) +4698867*a(n-13) -5265061*a(n-14) +6840484*a(n-15) -5130611*a(n-16) +7218027*a(n-17) -3378370*a(n-18) +4680079*a(n-19) -2705514*a(n-20) -157208*a(n-21) -4245554*a(n-22) -4490128*a(n-23) -5765472*a(n-24) -5764538*a(n-25) -5166552*a(n-26) -4254715*a(n-27) -3098347*a(n-28) -2091098*a(n-29) -1271422*a(n-30) -706430*a(n-31) -357345*a(n-32) -162833*a(n-33) -67173*a(n-34) -24634*a(n-35) -7967*a(n-36) -2242*a(n-37) -526*a(n-38) -100*a(n-39) -14*a(n-40) -a(n-41)

EXAMPLE

Some solutions for n=4

..0..0....2..2....4..4....3..3....1..1....5..5....5..5....2..2....2..2....0..0

..3..3....2..2....4..4....4..4....1..1....5..5....5..5....5..5....5..5....2..2

..5..5....1..1....2..2....5..5....2..2....5..5....5..5....5..5....5..5....4..4

..5..5....0..0....2..2....5..5....2..2....5..5....1..1....5..5....5..5....4..4

CROSSREFS

Sequence in context: A225012 A228458 A203050 * A190065 A293068 A213294

Adjacent sequences:  A203329 A203330 A203331 * A203333 A203334 A203335

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 31 2011

STATUS

approved

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Last modified April 22 14:20 EDT 2021. Contains 343177 sequences. (Running on oeis4.)