A250374 Number of length 1+6 0..n arrays with every seven consecutive terms having the maximum of some three terms equal to the minimum of the remaining four terms.

93, 1382, 8964, 37385, 118621, 312578, 720112, 1498569, 2879845, 5190966, 8877188, 14527617, 22903349, 34968130, 51921536, 75234673, 106688397, 148414054, 202936740, 273221081, 362719533, 475423202, 615915184, 789426425, 1001894101

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 + (161/6)*n^3 + (63/4)*n^2 + (17/3)*n + 1.

Conjectures from Colin Barker, Nov 13 2018: (Start)

G.f.: x*(93 + 731*x + 1243*x^2 + 404*x^3 + 55*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....3....1....1....2....1....3....3....2....3....4....3....1....0....4
..5....4....5....5....3....0....1....1....3....4....3....2....3....5....3....4
..2....5....1....2....1....0....5....0....1....5....3....5....3....0....1....4
..1....1....2....3....2....0....0....1....2....3....3....5....5....3....1....2
..0....0....1....2....0....4....3....1....1....0....3....2....0....3....4....3
..1....1....5....1....4....4....0....5....2....3....2....0....4....5....1....0
..3....0....2....2....0....0....2....5....5....3....3....2....2....3....1....3

Crossrefs

Row 1 of A250373.

Sequence in context: A332614 A264556 A250373 * A146125 A353002 A017809

Adjacent sequences: A250371 A250372 A250373 * A250375 A250376 A250377

Keyword

nonn

Author

R. H. Hardin, Nov 19 2014

Status

approved