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A249962 Number of length 2+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, 505, 5300, 31180, 129095, 422065, 1164800, 2830080, 6226935, 12655665, 24104740, 43494620, 74973535, 124270265, 199108960, 309691040, 469249215, 694678665, 1007250420, 1433411980, 2005680215, 2763631585, 3754994720 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 2 of A249960.

LINKS

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

FORMULA

Empirical: a(n) = n^7 + (13/6)*n^6 + (13/3)*n^5 + (65/12)*n^4 + (3/2)*n^3 - (1/12)*n^2 + (2/3)*n.

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

G.f.: 5*x*(1 + x)*(3 + 74*x + 262*x^2 + 154*x^3 + 11*x^4) / (1 - x)^8.

a(n) = 8*a(n-1) - 28*a(n-2) + 56*a(n-3) - 70*a(n-4) + 56*a(n-5) - 28*a(n-6) + 8*a(n-7) - a(n-8) for n>8.

(End)

EXAMPLE

Some solutions for n=5:

..1....5....2....1....3....0....5....2....3....2....3....3....1....3....1....2

..4....1....1....2....4....2....0....3....0....2....0....0....5....0....1....0

..5....5....0....4....0....3....5....0....5....2....5....3....4....1....2....0

..3....5....3....1....4....5....1....1....5....0....4....1....5....3....3....4

..0....3....4....3....5....0....0....2....1....0....0....4....5....3....3....4

..2....5....2....5....0....5....3....0....5....5....2....3....2....3....2....3

..0....5....2....1....2....5....1....4....2....3....5....3....3....0....1....3

CROSSREFS

Sequence in context: A208099 A219057 A203525 * A004703 A218188 A218365

Adjacent sequences:  A249959 A249960 A249961 * A249963 A249964 A249965

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 09 2014

STATUS

approved

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Last modified February 25 12:53 EST 2021. Contains 341607 sequences. (Running on oeis4.)