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A249848
Number of length 4+4 0..n arrays with no five consecutive terms having the maximum of any two terms equal to the minimum of the remaining three terms.
1
10, 653, 11052, 92190, 499654, 2029683, 6712760, 19039308, 47942370, 109802473, 232780196, 462822282, 871727454, 1567698415, 2708846832, 4520158424, 7314465594, 11518015365, 17701260700, 26615543606, 39236378742, 56814086571
OFFSET
1,1
COMMENTS
Row 4 of A249844.
LINKS
FORMULA
Empirical: a(n) = n^8 + (13/21)*n^7 + (101/30)*n^6 + (71/30)*n^5 + (2/3)*n^4 + 2*n^3 - (1/30)*n^2 + (1/70)*n.
Conjectures from Colin Barker, Aug 18 2017: (Start)
G.f.: x*(10 + 563*x + 5535*x^2 + 15390*x^3 + 14224*x^4 + 4287*x^5 + 311*x^6) / (1 - x)^9.
a(n) = 9*a(n-1) - 36*a(n-2) + 84*a(n-3) - 126*a(n-4) + 126*a(n-5) - 84*a(n-6) + 36*a(n-7) - 9*a(n-8) + a(n-9) for n>9.
(End)
EXAMPLE
Some solutions for n=4
..0....2....0....4....3....3....2....0....3....2....3....4....0....0....2....4
..4....4....2....4....0....1....0....4....0....0....1....1....3....4....4....1
..1....4....2....4....3....3....1....1....2....4....3....0....2....3....3....4
..0....4....0....3....4....0....0....3....4....0....0....0....0....0....0....4
..3....2....1....0....2....3....3....2....0....3....0....3....1....2....1....2
..2....1....4....1....0....2....1....0....4....3....4....2....0....0....0....1
..0....0....2....0....1....0....0....0....3....2....1....4....3....4....1....1
..2....4....2....3....3....1....1....2....2....1....2....3....2....2....4....4
CROSSREFS
Sequence in context: A280897 A099024 A126680 * A214108 A174061 A058174
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 07 2014
STATUS
approved