A249851 Number of length 7+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.

10, 3966, 223505, 4527441, 49270055, 354521087, 1901506446, 8194431990, 29822392392, 94893269020, 270701817639, 705393878111, 1703213060445, 3853520547653, 8242557895820, 16788311912316, 32753314777686

Offset

1,1

Comments

Row 7 of A249844.

Links

R. H. Hardin, Table of n, a(n) for n = 1..55

Formula

Empirical: a(n) = n^11 - (118/105)*n^10 + (99637/15120)*n^9 - (27427/5040)*n^8 + (339/40)*n^7 + (33/20)*n^6 - (4957/720)*n^5 + (15979/1680)*n^4 - (34751/7560)*n^3 + (1019/2520)*n^2 + (5/12)*n.

Conjectures from Colin Barker, Aug 18 2017: (Start)

G.f.: x*(10 + 3846*x + 176573*x^2 + 2104937*x^3 + 8824523*x^4 + 14875683*x^5 + 10543155*x^6 + 3058279*x^7 + 321259*x^8 + 8535*x^9) / (1 - x)^12.

a(n) = 12*a(n-1) - 66*a(n-2) + 220*a(n-3) - 495*a(n-4) + 792*a(n-5) - 924*a(n-6) + 792*a(n-7) - 495*a(n-8) + 220*a(n-9) - 66*a(n-10) + 12*a(n-11) - a(n-12) for n>12.

(End)

Example

Some solutions for n=2
..0....0....2....2....2....0....0....1....2....1....0....2....1....0....1....2
..1....0....1....0....0....1....0....2....0....0....2....0....0....1....2....0
..1....1....2....1....2....2....2....2....0....2....2....0....0....2....2....1
..0....1....0....2....0....2....1....2....2....2....1....1....2....2....0....0
..2....1....0....0....2....0....1....0....1....2....0....1....1....2....2....2
..0....0....2....2....2....2....0....0....2....1....2....1....2....0....1....1
..1....0....1....2....0....1....0....2....0....0....0....0....2....1....2....0
..2....1....1....1....1....2....2....1....2....2....1....0....0....2....0....1
..2....1....0....2....2....0....2....2....0....2....1....1....2....0....0....0
..0....2....0....1....0....2....1....0....1....2....0....1....1....1....1....2
..2....0....2....2....1....2....0....2....2....0....2....2....2....0....2....2

Crossrefs

Sequence in context: A154238 A234144 A291676 * A024139 A320983 A316397

Adjacent sequences: A249848 A249849 A249850 * A249852 A249853 A249854

Keyword

nonn

Author

R. H. Hardin, Nov 07 2014

Status

approved