A207010 Number of nX3 0..2 arrays avoiding the patterns z z+1 z or z z-1 z in any row or column

23, 529, 7891, 130165, 2113177, 34303001, 555815721, 9009608765, 146090588449, 2369000508453, 38413524599409, 622859701218333, 10099430425592569, 163759482495029077, 2655320116135400321, 43055336278469375613

Offset

1,1

Comments

Column 3 of A207015

Links

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

Formula

Empirical: a(n) = 17*a(n-1) -62*a(n-2) +504*a(n-3) +4150*a(n-4) +5956*a(n-5) +52500*a(n-6) +324172*a(n-7) -312336*a(n-8) -7411552*a(n-9) -17702840*a(n-10) +3602080*a(n-11) +84650816*a(n-12) +197673664*a(n-13) +227286144*a(n-14) +39420416*a(n-15) -347133568*a(n-16) -622917632*a(n-17) -875376640*a(n-18) -427984896*a(n-19) -202702848*a(n-20) +417185792*a(n-21) +142204928*a(n-22) +58327040*a(n-23) -46792704*a(n-24) +1310720*a(n-25)

Example

Some solutions for n=4
..0..0..2....2..1..0....2..2..0....1..2..2....1..2..2....2..0..1....2..2..1
..0..0..2....2..1..0....0..0..2....0..0..1....2..1..0....0..0..2....2..0..0
..0..0..0....2..1..1....2..0..0....2..2..0....2..0..1....1..1..2....2..0..0
..1..2..0....0..1..1....1..0..2....1..2..2....2..2..1....1..1..1....2..2..2

Crossrefs

Sequence in context: A014960 A207230 A207223 * A171297 A009967 A147642

Adjacent sequences: A207007 A207008 A207009 * A207011 A207012 A207013

Keyword

nonn

Author

R. H. Hardin Feb 14 2012

Status

approved