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A255627 Number of length n+5 0..2 arrays with at most two downsteps in every n consecutive neighbor pairs 1
729, 2187, 6561, 17622, 40659, 83325, 156563, 275166, 458604, 731981, 1127139, 1683927, 2451654, 3490746, 4874628, 6691853, 9048501, 12070872, 15908498, 20737500, 26764317, 34229835, 43413945, 54640560, 68283122, 84770631 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 5 of A255622

LINKS

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

FORMULA

Empirical: a(n) = (1/40320)*n^8 + (19/10080)*n^7 + (31/576)*n^6 + (122/45)*n^5 + (188527/5760)*n^4 + (32263/1440)*n^3 + (276001/672)*n^2 - (152493/280)*n + 387 for n>3

EXAMPLE

Some solutions for n=4

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

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

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

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

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

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

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

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

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

CROSSREFS

Cf. A255622

Sequence in context: A267697 A232925 A255112 * A139308 A295024 A167728

Adjacent sequences:  A255624 A255625 A255626 * A255628 A255629 A255630

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 28 2015

STATUS

approved

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Last modified December 13 17:30 EST 2017. Contains 295959 sequences.