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A256822 Number of length n+7 0..1 arrays with at most two downsteps in every n consecutive neighbor pairs. 1
256, 512, 1024, 2048, 3728, 6192, 9613, 14168, 20075, 27566, 36888, 48304, 62094, 78556, 98007, 120784, 147245, 177770, 212762, 252648, 297880, 348936, 406321, 470568, 542239, 621926, 710252, 807872, 915474, 1033780, 1163547, 1305568 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 7 of A256816.

LINKS

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

FORMULA

Empirical: a(n) = (1/120)*n^5 + (1/4)*n^4 + (193/8)*n^3 - (169/4)*n^2 + (8323/15)*n - 1216 for n>5.

Empirical g.f.: x*(256 - 1024*x + 1792*x^2 - 1536*x^3 + 400*x^4 + 208*x^5 - 35*x^6 - 102*x^7 + 78*x^8 - 64*x^9 + 28*x^10) / (1 - x)^6. - Colin Barker, Jan 21 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

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

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

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

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

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

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

CROSSREFS

Cf. A256816.

Sequence in context: A255998 A309092 A043336 * A172422 A031465 A045081

Adjacent sequences:  A256819 A256820 A256821 * A256823 A256824 A256825

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 10 2015

STATUS

approved

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Last modified November 18 04:44 EST 2019. Contains 329248 sequences. (Running on oeis4.)