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A200889 Number of 0..n arrays x(0..5) of 6 elements without any interior element greater than both neighbors. 1
37, 292, 1268, 3985, 10213, 22736, 45648, 84681, 147565, 244420, 388180, 595049, 884989, 1282240, 1815872, 2520369, 3436245, 4610692, 6098260, 7961569, 10272053, 13110736, 16569040, 20749625, 25767261, 31749732, 38838772, 47191033, 56979085 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 4 of A200886.

LINKS

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

FORMULA

Empirical: a(n) = (2/45)*n^6 + (19/15)*n^5 + (217/36)*n^4 + (71/6)*n^3 + (2057/180)*n^2 + (27/5)*n + 1.

Conjectures from Colin Barker, Oct 16 2017: (Start)

G.f.: x*(37 + 33*x + x^2 - 54*x^3 + 21*x^4 - 7*x^5 + x^6) / (1 - x)^7.

a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n>7.

(End)

EXAMPLE

Some solutions for n=3

..1....0....3....0....2....2....1....0....1....3....2....3....2....2....3....2

..0....1....1....3....1....3....1....0....1....0....2....3....3....1....1....2

..1....2....0....3....3....3....2....0....0....1....1....0....3....0....3....2

..3....2....1....0....3....2....2....1....1....2....0....0....1....0....3....2

..3....2....2....0....1....2....3....2....2....2....1....2....0....2....2....1

..3....3....2....3....1....0....3....2....2....1....2....2....3....3....2....0

CROSSREFS

Sequence in context: A165381 A086840 A190418 * A211156 A217642 A197340

Adjacent sequences:  A200886 A200887 A200888 * A200890 A200891 A200892

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 23 2011

STATUS

approved

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Last modified January 26 09:09 EST 2022. Contains 350597 sequences. (Running on oeis4.)