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A249845 Number of length 1+4 0..n arrays with no five consecutive terms having the maximum of any two terms equal to the minimum of the remaining three terms. 1
10, 110, 560, 1920, 5170, 11830, 24080, 44880, 78090, 128590, 202400, 306800, 450450, 643510, 897760, 1226720, 1645770, 2172270, 2825680, 3627680, 4602290, 5775990, 7177840, 8839600, 10795850, 13084110, 15744960, 18822160, 22362770 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 1 of A249844.

LINKS

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

FORMULA

Empirical: a(n) = n^5 + (5/2)*n^4 + (10/3)*n^3 + (5/2)*n^2 + (2/3)*n.

Conjectures from Colin Barker, Aug 18 2017: (Start)

G.f.: 10*x*(1 + x)*(1 + 4*x + x^2) / (1 - x)^6.

a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>6.

(End)

EXAMPLE

Some solutions for n=6

..5....6....6....3....5....0....4....5....4....0....3....1....6....0....3....5

..0....3....6....4....3....5....1....4....3....1....5....2....3....1....1....3

..6....0....2....3....2....0....6....6....2....0....4....3....5....0....5....1

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

..2....5....3....1....6....6....2....1....5....2....0....3....6....2....4....0

CROSSREFS

Sequence in context: A043996 A044723 A158492 * A180290 A110251 A270243

Adjacent sequences:  A249842 A249843 A249844 * A249846 A249847 A249848

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 07 2014

STATUS

approved

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Last modified October 20 22:44 EDT 2019. Contains 328291 sequences. (Running on oeis4.)