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A250338 Number of length 2+5 0..n arrays with every six consecutive terms having the maximum of some three terms equal to the minimum of the remaining three terms. 1
68, 907, 5264, 20085, 59396, 147903, 325312, 651369, 1211620, 2123891, 3545488, 5681117, 8791524, 13202855, 19316736, 27621073, 38701572, 53253979, 72097040, 96186181, 126627908, 164694927, 211841984, 269722425, 340205476, 425394243 (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) = n^6 + 9*n^5 + 20*n^4 + (68/3)*n^3 + 12*n^2 + (7/3)*n + 1.

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

G.f.: x*(68 + 431*x + 343*x^2 - 96*x^3 - 20*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=6:

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

..1....0....4....6....5....0....5....5....2....2....2....2....4....5....0....5

..3....2....5....2....5....2....6....2....2....0....1....4....3....5....6....3

..3....2....6....3....5....2....6....0....3....1....2....3....4....2....0....5

..4....5....4....2....3....2....3....2....4....5....5....3....6....2....0....5

..3....6....1....0....5....4....5....2....2....2....1....3....6....0....0....5

..5....1....4....2....0....4....0....0....1....5....5....6....1....2....4....4

CROSSREFS

Row 2 of A250336.

Sequence in context: A200876 A039507 A250144 * A223374 A254645 A281049

Adjacent sequences:  A250335 A250336 A250337 * A250339 A250340 A250341

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 19 2014

STATUS

approved

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Last modified May 24 14:36 EDT 2022. Contains 354037 sequences. (Running on oeis4.)