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A249964 Number of length 4+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, 1593, 37584, 402010, 2662039, 12791191, 48882360, 157381572, 443628615, 1124698773, 2615110872, 5658900702, 11524855615, 22285365715, 41203369552, 73256257608, 125830345119, 209624636913, 339808080960, 537480344226 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 4 of A249960.

LINKS

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

FORMULA

Empirical: a(n) = n^9 + (107/140)*n^8 + (309/70)*n^7 + (187/45)*n^6 - (43/60)*n^5 + (751/180)*n^4 + (113/60)*n^3 - (1003/630)*n^2 + (193/210)*n.

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

G.f.: (15 + 1443*x + 22329*x^2 + 96055*x^3 + 145209*x^4 + 81921*x^5 + 15359*x^6 + 549*x^7) / (1 - x)^10.

a(n) = 10*a(n-1) - 45*a(n-2) + 120*a(n-3) - 210*a(n-4) + 252*a(n-5) - 210*a(n-6) + 120*a(n-7) - 45*a(n-8) + 10*a(n-9) - a(n-10) for n>10.

(End)

EXAMPLE

Some solutions for n=3:

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

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

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

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

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

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

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

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

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

CROSSREFS

Sequence in context: A209681 A209682 A209683 * A281801 A208000 A182925

Adjacent sequences:  A249961 A249962 A249963 * A249965 A249966 A249967

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 09 2014

STATUS

approved

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Last modified March 4 02:37 EST 2021. Contains 341774 sequences. (Running on oeis4.)