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.

107, 1452, 9160, 37805, 119391, 313852, 722072, 1501425, 2883835, 5196356, 8884272, 14536717, 22914815, 34982340, 51938896, 75255617, 106713387, 148443580, 202971320, 273261261, 362765887, 475476332, 615975720, 789495025

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: A113932 A357551 A250154 * A240596 A185677 A262658

Adjacent sequences: A250152 A250153 A250154 * A250156 A250157 A250158

Keyword

nonn

Author

R. H. Hardin, Nov 13 2014

Status

approved