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A233921 Number of (n+1) X (1+1) 0..4 arrays with every 2 X 2 subblock having the sum of the absolute values of the edge differences equal to 8 and no adjacent elements equal. 1
98, 518, 2792, 15230, 83290, 456328, 2500838, 13709358, 75155340, 412023922, 2258839434, 12383734204, 67891856922, 372206825758, 2040567205064, 11187101456262, 61331590903554, 336241181497880, 1843391459226238 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 6*a(n-1) + 5*a(n-2) - 46*a(n-3) + 5*a(n-4) + 60*a(n-5) + 20*a(n-6).
Empirical g.f.: 2*x*(49 - 35*x - 403*x^2 + 198*x^3 + 644*x^4 + 200*x^5) / ((1 - 2*x)*(1 - 4*x - 13*x^2 + 20*x^3 + 35*x^4 + 10*x^5)). - Colin Barker, Oct 12 2018
EXAMPLE
Some solutions for n=5:
..0..2....1..4....2..3....3..1....3..0....1..0....0..2....3..2....0..1....1..0
..3..1....0..2....4..1....0..2....2..3....2..4....4..3....0..3....3..0....0..3
..2..4....3..4....3..4....2..4....4..1....0..2....3..0....3..4....0..1....1..0
..0..3....0..1....0..2....0..2....2..0....1..4....4..1....2..0....3..0....4..3
..1..4....2..4....4..3....2..0....4..1....4..3....3..4....3..4....2..3....0..2
..0..3....4..2....1..0....4..3....2..0....1..0....0..2....0..3....0..4....4..3
CROSSREFS
Column 1 of A233928.
Sequence in context: A263033 A239173 A233928 * A203083 A202370 A184608
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 17 2013
STATUS
approved

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Last modified June 25 13:13 EDT 2024. Contains 373705 sequences. (Running on oeis4.)