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A249884 Number of length 1+6 0..n arrays with no seven consecutive terms having the maximum of any three terms equal to the minimum of the remaining four terms. 1
35, 805, 7420, 40740, 161315, 510965, 1377040, 3284400, 7120155, 14296205, 26954620, 48220900, 82510155, 135891245, 216513920, 335104000, 505531635, 745457685, 1077063260, 1527867460, 2131638355, 2929402245, 3970556240 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = n^7 + (7/2)*n^6 + 7*n^5 + (35/4)*n^4 + (49/6)*n^3 + (21/4)*n^2 + (4/3)*n.
Conjectures from Colin Barker, Nov 10 2018: (Start)
G.f.: 35*x*(1 + x)*(1 + 4*x + x^2)*(1 + 10*x + x^2) / (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=5:
..2....1....1....0....2....0....0....1....0....4....0....2....0....2....1....1
..5....2....5....1....0....5....2....3....2....0....2....3....3....0....4....1
..2....1....0....5....2....5....5....0....3....0....3....4....5....1....5....5
..5....5....0....5....1....2....2....0....0....3....3....4....2....4....1....4
..1....5....0....3....0....0....4....0....0....3....5....4....4....3....5....5
..0....3....2....1....3....3....0....3....5....2....0....0....4....5....4....1
..1....0....3....3....3....4....0....3....3....4....3....0....4....1....3....2
CROSSREFS
Row 1 of A249883.
Sequence in context: A028024 A226941 A249883 * A223957 A109508 A267834
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 07 2014
STATUS
approved

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Last modified May 27 02:41 EDT 2024. Contains 372847 sequences. (Running on oeis4.)