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A185535 1/6 the number of n X 2 0..5 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors. 1
1, 11, 110, 1155, 12105, 127190, 1336205, 14039455, 147510990, 1549891055, 16284627805, 171101820790, 1797758782905, 18888967243155, 198465493076590, 2085267630701755, 21909809227375505, 230205338311698390 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Column 2 of A185540.
LINKS
FORMULA
Empirical: a(n) = 9*a(n-1) + 19*a(n-2) - 25*a(n-3) - 75*a(n-4) - 125*a(n-5).
Empirical g.f.: x*(1 + 2*x - 8*x^2 - 19*x^3 - 30*x^4) / (1 - 9*x - 19*x^2 + 25*x^3 + 75*x^4 + 125*x^5). - Colin Barker, Apr 16 2018
EXAMPLE
Some solutions for 3 X 2 with a(1,1)=0:
..0..4....0..0....0..0....0..0....0..0....0..0....0..3....0..5....0..0....0..5
..0..4....5..1....0..5....1..1....1..3....0..2....0..3....0..5....2..0....0..5
..0..4....5..1....0..5....3..3....1..3....2..2....3..3....3..3....2..0....5..5
CROSSREFS
Cf. A185540.
Sequence in context: A285561 A285541 A355407 * A281601 A266513 A356329
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 30 2011
STATUS
approved

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Last modified February 22 11:38 EST 2024. Contains 370255 sequences. (Running on oeis4.)