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A248457 Number of length n+2 0..4 arrays with no three consecutive terms having the sum of any two elements equal to twice the third. 1
96, 380, 1512, 6040, 24160, 96736, 387488, 1552448, 6220480, 24926080, 99883840, 400260160, 1603955712, 6427525312, 25757039296, 103216337152, 413619611968, 1657501354048, 6642119813120, 26617026736320, 106662654436544 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) + 5*a(n-2) + 2*a(n-3) - 16*a(n-4) - 28*a(n-5) - 8*a(n-6).
Empirical g.f.: 4*x*(24 + 23*x - 27*x^2 - 147*x^3 - 186*x^4 - 50*x^5) / ((1 - 2*x)*(1 - x - 7*x^2 - 16*x^3 - 16*x^4 - 4*x^5)). - Colin Barker, Nov 08 2018
EXAMPLE
Some solutions for n=6:
..1....0....0....2....3....3....0....0....3....2....3....1....3....4....0....1
..3....4....1....0....4....4....3....1....1....3....2....4....2....1....3....3
..0....1....3....3....4....3....4....1....0....0....2....2....2....4....0....0
..0....4....4....1....3....0....0....0....3....4....3....2....3....4....2....0
..2....1....3....4....1....4....1....4....0....1....2....0....3....0....3....1
..3....0....0....3....1....0....3....4....2....2....0....0....1....0....0....1
..0....1....2....1....2....0....4....2....2....4....0....4....3....4....2....3
..0....0....0....0....4....4....3....2....3....1....3....4....3....3....3....1
CROSSREFS
Column 4 of A248461.
Sequence in context: A292345 A084048 A167983 * A051483 A277107 A292543
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 06 2014
STATUS
approved

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Last modified July 22 16:15 EDT 2024. Contains 374540 sequences. (Running on oeis4.)