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A250155 Number of length 1+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
107, 1452, 9160, 37805, 119391, 313852, 722072, 1501425, 2883835, 5196356, 8884272, 14536717, 22914815, 34982340, 51938896, 75255617, 106713387, 148443580, 202971320, 273261261, 362765887, 475476332, 615975720, 789495025 (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) = (7/2)*n^6 + 14*n^5 + (105/4)*n^4 + (63/2)*n^3 + (91/4)*n^2 + 8*n + 1.

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

G.f.: x*(107 + 703*x + 1243*x^2 + 432*x^3 + 41*x^4 - 7*x^5 + x^6) / (1 - x)^7.

a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n>7.

(End)

EXAMPLE

Some solutions for n=5:

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

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

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

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

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

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

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

CROSSREFS

Row 1 of A250154.

Sequence in context: A212377 A113932 A250154 * A240596 A185677 A262658

Adjacent sequences:  A250152 A250153 A250154 * A250156 A250157 A250158

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 13 2014

STATUS

approved

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Last modified June 21 15:37 EDT 2021. Contains 345364 sequences. (Running on oeis4.)