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A255990 Number of length n+6 0..1 arrays with at most one downstep in every 6 consecutive neighbor pairs. 1
64, 98, 156, 257, 428, 705, 1134, 1797, 2848, 4560, 7384, 12021, 19508, 31444, 50432, 80828, 129904, 209549, 338650, 546939, 881612, 1418697, 2281990, 3673412, 5919888, 9546459, 15393334, 24807246, 39956320, 64344494, 103638460, 166985169 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 6 of A255992.
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) -a(n-2) +5*a(n-6) -4*a(n-7).
Empirical g.f.: x*(64 - 30*x + 24*x^2 + 43*x^3 + 70*x^4 + 106*x^5 - 168*x^6) / (1 - 2*x + x^2 - 5*x^6 + 4*x^7). - Colin Barker, Jan 24 2018
EXAMPLE
Some solutions for n=4:
..0....0....0....0....0....0....0....0....0....1....0....0....0....0....0....0
..0....1....0....0....0....0....1....1....1....1....0....0....0....1....0....1
..0....0....0....0....0....0....1....0....0....1....0....0....1....0....0....0
..0....0....0....0....0....0....0....0....0....1....0....0....0....0....0....1
..0....0....1....1....0....1....0....0....1....1....0....1....0....0....0....1
..0....0....1....0....1....0....0....0....1....1....0....0....0....0....0....1
..0....1....1....0....1....0....0....1....1....0....0....1....0....0....1....1
..0....1....1....0....1....0....0....1....1....0....1....1....0....1....0....1
..0....0....1....1....1....0....0....0....0....0....1....1....0....1....0....1
..0....1....0....1....1....0....0....0....1....0....0....1....0....1....1....0
CROSSREFS
Cf. A255992.
Sequence in context: A223086 A175163 A111730 * A104022 A061099 A118488
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 13 2015
STATUS
approved

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Last modified April 13 10:11 EDT 2024. Contains 371640 sequences. (Running on oeis4.)