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A255989 Number of length n+5 0..1 arrays with at most one downstep in every 5 consecutive neighbor pairs. 1
42, 68, 114, 196, 337, 568, 945, 1574, 2645, 4476, 7568, 12736, 21365, 35852, 60308, 101608, 171148, 287940, 484045, 813826, 1369115, 2304172, 3877545, 6523278, 10972180, 18456064, 31049291, 52240182, 87891550, 147861804, 248739774 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 5 of A255992.
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) -a(n-2) +4*a(n-5) -3*a(n-6).
Empirical g.f.: x*(42 - 16*x + 20*x^2 + 36*x^3 + 59*x^4 - 78*x^5) / ((1 + x - x^3)*(1 - 3*x + 4*x^2 - 3*x^3)). - Colin Barker, Jan 24 2018
EXAMPLE
Some solutions for n=4:
..1....0....1....0....0....1....0....0....0....0....0....0....1....1....0....1
..1....1....0....1....0....0....0....1....1....0....0....1....1....1....1....0
..0....1....1....0....1....0....1....0....0....1....0....0....0....0....0....0
..0....1....1....1....1....0....1....0....0....0....0....0....0....0....0....1
..1....1....1....1....1....0....1....0....1....0....0....0....0....1....0....1
..1....1....1....1....1....1....1....0....1....0....0....1....1....1....0....1
..1....1....0....1....0....1....1....0....1....1....1....1....1....1....1....1
..0....1....0....0....0....0....0....1....1....1....0....0....1....0....0....1
..0....1....0....1....0....0....0....0....1....0....0....0....0....1....1....0
CROSSREFS
Cf. A255992.
Sequence in context: A350641 A115957 A362003 * A192274 A291319 A226168
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 13 2015
STATUS
approved

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Last modified April 22 00:17 EDT 2024. Contains 371886 sequences. (Running on oeis4.)