A188976 - OEIS

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A188976

Number of nX2 array permutations with each element moved but moved no more than a city block distance of two

1, 9, 116, 900, 7836, 71865, 640513, 5706113, 51056136, 456396688, 4078122040, 36448590305, 325763780945, 2911451082361, 26020738951500, 232557947597540, 2078461123504804, 18576017680577225, 166021162669244641

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Column 2 of A188981

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = 8*a(n-1) +3*a(n-2) +68*a(n-3) -142*a(n-4) -354*a(n-5) +225*a(n-6) +430*a(n-7) +47*a(n-8) +308*a(n-9) -16*a(n-10) -932*a(n-11) +281*a(n-12) +24*a(n-13) -195*a(n-14) +112*a(n-15) +22*a(n-16) +22*a(n-17) -a(n-18) -6*a(n-19) +a(n-20)

EXAMPLE

Some solutions for 3X2

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

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

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

CROSSREFS

Sequence in context: A362774 A157233 A292350 * A180913 A341964 A083305

Adjacent sequences: A188973 A188974 A188975 * A188977 A188978 A188979

KEYWORD

nonn

AUTHOR

R. H. Hardin Apr 14 2011

STATUS

approved