[go: up one dir, main page]

login
A250064
Number of length 4+6 0..n arrays with no seven consecutive terms having the maximum of any two terms equal to the minimum of the remaining five terms.
1
21, 4030, 132054, 1800040, 14492075, 82072086, 361440380, 1318262304, 4153110705, 11640299550, 29654571826, 69781269480, 153557285479, 319076606870, 630919231800, 1194629311616, 2177281160205, 3836033915454
OFFSET
1,1
COMMENTS
Row 4 of A250059.
LINKS
FORMULA
Empirical: a(n) = n^10 + n^9 + (40/7)*n^8 + 7*n^7 - (11/6)*n^6 + (20/3)*n^5 + (25/6)*n^4 - (25/6)*n^3 + (61/42)*n^2.
Conjectures from Colin Barker, Aug 22 2017: (Start)
G.f.: x*(21 + 3799*x + 88879*x^2 + 565631*x^3 + 1296585*x^4 + 1192749*x^5 + 430621*x^6 + 49661*x^7 + 854*x^8) / (1 - x)^11.
a(n) = 11*a(n-1) - 55*a(n-2) + 165*a(n-3) - 330*a(n-4) + 462*a(n-5) - 462*a(n-6) + 330*a(n-7) - 165*a(n-8) + 55*a(n-9) - 11*a(n-10) + a(n-11) for n>11.
(End)
EXAMPLE
Some solutions for n=3:
..1....2....2....1....1....1....2....1....0....2....1....3....3....1....3....2
..3....2....2....1....0....3....1....3....2....2....2....0....1....3....1....2
..0....2....1....0....0....1....2....2....0....1....2....2....0....0....1....0
..3....1....0....1....2....0....0....0....1....3....3....3....0....1....0....2
..2....0....2....0....2....3....2....1....3....3....0....0....1....3....3....1
..3....0....0....3....2....2....0....3....3....0....3....1....3....0....0....0
..3....2....3....3....3....0....3....0....3....3....2....2....3....2....2....2
..1....3....1....3....1....3....2....2....2....2....0....2....2....2....2....3
..2....2....2....3....0....2....2....2....2....0....3....0....2....3....3....3
..0....3....3....0....3....1....3....2....1....2....1....2....2....2....1....2
CROSSREFS
Sequence in context: A153833 A221164 A264250 * A200998 A209473 A055416
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 11 2014
STATUS
approved