A203332 Number of nX2 0..5 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors

1, 6, 36, 161, 846, 5545, 35483, 216488, 1340730, 8480848, 53643799, 338093942, 2134537993, 13508527719, 85530509012, 541535824313, 3429939732074, 21732616374723, 137726568471728, 872907436160530, 5533065935012257

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 * A351783 A190065 A293068

Adjacent sequences: A203329 A203330 A203331 * A203333 A203334 A203335

Keyword

nonn

Author

R. H. Hardin Dec 31 2011

Status

approved