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A255628 Number of length n+6 0..2 arrays with at most two downsteps in every n consecutive neighbor pairs 1
2187, 6561, 19683, 51768, 114546, 225253, 405687, 685713, 1103630, 1707576, 2557098, 3724906, 5298831, 7384008, 10105306, 13610028, 18070905, 23689409, 30699411, 39371211, 50015968, 62990559, 78702897, 97617739, 120263016 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 6 of A255622

LINKS

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

FORMULA

Empirical: a(n) = (1/40320)*n^8 + (1/480)*n^7 + (13/192)*n^6 + (67/12)*n^5 + (48663/640)*n^4 + (46699/480)*n^3 + (5325055/2016)*n^2 - (53947/8)*n + 3866 for n>4

EXAMPLE

Some solutions for n=4

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

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

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

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

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

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

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

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

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

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

CROSSREFS

Cf. A255622

Sequence in context: A046320 A232926 A255113 * A232287 A219134 A233160

Adjacent sequences:  A255625 A255626 A255627 * A255629 A255630 A255631

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 28 2015

STATUS

approved

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Last modified January 25 03:44 EST 2022. Contains 350565 sequences. (Running on oeis4.)