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A255997 Number of length n+6 0..1 arrays with at most one downstep in every n consecutive neighbor pairs. 1
128, 256, 354, 451, 568, 705, 854, 1016, 1192, 1383, 1590, 1814, 2056, 2317, 2598, 2900, 3224, 3571, 3942, 4338, 4760, 5209, 5686, 6192, 6728, 7295, 7894, 8526, 9192, 9893, 10630, 11404, 12216, 13067, 13958, 14890, 15864, 16881, 17942, 19048, 20200 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 6 of A255992.

LINKS

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

FORMULA

Empirical: a(n) = (1/6)*n^3 + 3*n^2 + (533/6)*n + 28 for n>4.

Empirical g.f.: x*(128 - 256*x + 98*x^2 + 59*x^3 - 8*x^4 - 21*x^5 - 8*x^6 + 9*x^7) / (1 - x)^4. - Colin Barker, Jan 26 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

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

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

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

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

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

CROSSREFS

Cf. A255992.

Sequence in context: A046308 A110290 A045028 * A256821 A172421 A235059

Adjacent sequences:  A255994 A255995 A255996 * A255998 A255999 A256000

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 13 2015

STATUS

approved

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Last modified October 19 22:05 EDT 2021. Contains 348095 sequences. (Running on oeis4.)