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A249963 Number of length 3+5 0..n arrays with no six consecutive terms having the maximum of any two terms equal to the minimum of the remaining four terms. 1
15, 897, 14094, 111746, 585069, 2319123, 7532380, 21069828, 52478667, 119135973, 250738026, 495501318, 928465577, 1662329463, 2861289912, 4758396424, 7676971911, 12056692041, 18484955334, 27734216586, 40805996517, 58982320859 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 3 of A249960.

LINKS

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

FORMULA

Empirical: a(n) = n^8 + (152/105)*n^7 + (62/15)*n^6 + (26/5)*n^5 + (1/2)*n^4 + (19/15)*n^3 + (28/15)*n^2 - (29/70)*n.

Conjectures from Colin Barker, Aug 21 2017: (Start)

G.f.: x*(15 + 762*x + 6561*x^2 + 15932*x^3 + 13281*x^4 + 3594*x^5 + 175*x^6) / (1 - x)^9.

a(n) = 9*a(n-1) - 36*a(n-2) + 84*a(n-3) - 126*a(n-4) + 126*a(n-5) - 84*a(n-6) + 36*a(n-7) - 9*a(n-8) + a(n-9) for n>9.

(End)

EXAMPLE

Some solutions for n=4:

..4....1....4....0....1....4....3....3....1....3....3....0....2....2....0....1

..4....1....3....2....3....1....2....4....4....1....2....2....2....0....2....1

..0....0....0....3....0....0....3....0....0....2....0....4....3....0....2....0

..0....1....0....3....2....4....3....0....0....0....3....0....3....4....0....3

..4....2....4....1....1....0....0....2....3....1....1....1....3....4....4....0

..2....0....1....3....0....1....4....3....1....0....0....3....3....4....4....3

..4....2....3....1....1....2....0....4....1....3....4....4....0....4....1....4

..1....1....4....2....2....3....3....3....1....1....2....4....2....3....0....4

CROSSREFS

Sequence in context: A232364 A264562 A211109 * A157462 A268166 A042747

Adjacent sequences:  A249960 A249961 A249962 * A249964 A249965 A249966

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 09 2014

STATUS

approved

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Last modified October 27 10:47 EDT 2021. Contains 348274 sequences. (Running on oeis4.)