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A241608 Number of length n+2 0..2 arrays with no consecutive three elements summing to more than 2. 1
10, 20, 40, 76, 147, 287, 556, 1077, 2091, 4057, 7868, 15264, 29613, 57445, 111438, 216184, 419380, 813563, 1578253, 3061693, 5939450, 11522085, 22351978, 43361147, 84117349, 163181309, 316559417, 614101361, 1191310271, 2311051970, 4483266305 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) + a(n-2) + 2*a(n-3) - a(n-5) - a(n-6).

Empirical g.f.: x*(10 + 10*x + 10*x^2 - 4*x^3 - 9*x^4 - 6*x^5) / (1 - x - x^2 - 2*x^3 + x^5 + x^6). - Colin Barker, Oct 30 2018

EXAMPLE

Some solutions for n=5:

..1....0....2....0....1....2....2....1....0....1....1....0....1....1....1....0

..0....1....0....0....0....0....0....1....1....0....0....0....0....0....0....1

..1....0....0....0....1....0....0....0....0....1....1....0....1....0....0....0

..0....0....0....0....0....0....0....1....1....1....0....1....1....1....0....0

..0....2....0....0....0....1....0....1....1....0....0....0....0....0....1....0

..1....0....1....0....1....0....1....0....0....1....2....0....1....1....1....0

..1....0....0....2....0....0....1....0....0....0....0....2....1....0....0....0

CROSSREFS

Column 2 of A241619.

Sequence in context: A033846 A114931 A013978 * A053162 A110804 A048063

Adjacent sequences:  A241605 A241606 A241607 * A241609 A241610 A241611

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 26 2014

STATUS

approved

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Last modified December 10 14:27 EST 2019. Contains 329896 sequences. (Running on oeis4.)