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A250156 Number of length 2+6 0..n arrays with every seven consecutive terms having the maximum of some two terms equal to the minimum of the remaining five terms. 1
193, 3450, 26710, 129595, 468231, 1382188, 3522460, 8028405, 16761565, 32604286, 59831058, 104560495, 175295875, 283562160, 444647416, 678456553, 1010485305, 1472922370, 2105887630, 2958814371, 4091983423, 5578217140, 7504741140 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = (11/7)*n^7 + 13*n^6 + (67/2)*n^5 + (97/2)*n^4 + (103/2)*n^3 + 34*n^2 + (139/14)*n + 1.

Conjectures from Colin Barker, Nov 12 2018: (Start)

G.f.: x*(193 + 1906*x + 4514*x^2 + 1707*x^3 - 339*x^4 - 68*x^5 + 8*x^6 - x^7) / (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=4:

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

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

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

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

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

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

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

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

CROSSREFS

Row 2 of A250154.

Sequence in context: A166540 A178265 A201112 * A197112 A120851 A302332

Adjacent sequences:  A250153 A250154 A250155 * A250157 A250158 A250159

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 13 2014

STATUS

approved

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Last modified December 6 13:24 EST 2021. Contains 349563 sequences. (Running on oeis4.)