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A241609 Number of length n+2 0..3 arrays with no consecutive three elements summing to more than 3. 1
20, 50, 125, 295, 711, 1730, 4175, 10077, 24377, 58928, 142396, 344201, 832011, 2010980, 4860690, 11748840, 28397936, 68640170, 165909570, 401018224, 969296175, 2342874854, 5662936565, 13687818660, 33084669767, 79968578621 (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) = 2*a(n-1) + 4*a(n-3) - 3*a(n-4) - a(n-5) - 3*a(n-6) + 2*a(n-7) + a(n-9) - a(n-10).

Empirical g.f.: x*(20 + 10*x + 25*x^2 - 35*x^3 - 19*x^4 - 22*x^5 + 20*x^6 + 3*x^7 + 6*x^8 - 10*x^9) / ((1 - x)*(1 - x - x^2 - 5*x^3 - 2*x^4 - x^5 + 2*x^6 - x^9)). - Colin Barker, Oct 30 2018

EXAMPLE

Some solutions for n=5:

..1....2....3....2....1....0....3....0....1....1....1....1....1....3....2....0

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

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

..0....0....1....0....0....0....1....0....1....2....2....0....1....2....3....1

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

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

..3....1....1....0....0....1....0....1....1....2....0....0....1....2....1....3

CROSSREFS

Column 3 of A241619.

Sequence in context: A231293 A227771 A228023 * A049390 A220040 A128905

Adjacent sequences:  A241606 A241607 A241608 * A241610 A241611 A241612

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 26 2014

STATUS

approved

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Last modified December 7 22:29 EST 2019. Contains 329850 sequences. (Running on oeis4.)