login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A249967 Number of length 7+5 0..n arrays with no six consecutive terms having the maximum of any two terms equal to the minimum of the remaining four terms. 1
15, 8823, 709814, 18707320, 251002319, 2149795141, 13385651492, 65717571120, 268511791119, 948021599547, 2972106528666, 8443442678840, 22076610372895, 53774915777897, 123215084622184, 267660712891040, 554792683762767 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 7 of A249960.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..42

FORMULA

Empirical: a(n) = n^12 - (53/42)*n^11 + (1404/175)*n^10 - (8593/1260)*n^9 + (8647/1260)*n^8 + (3511/252)*n^7 - (43133/1800)*n^6 + (41323/2520)*n^5 + (21641/2520)*n^4 - (2225/168)*n^3 + (7339/1050)*n^2 - (158/105)*n.

Conjectures from Colin Barker, Aug 21 2017: (Start)

G.f.: x*(15 + 8628*x + 596285*x^2 + 10163642*x^3 + 60659998*x^4 + 149218290*x^5 + 162389570*x^6 + 78777198*x^7 + 16029715*x^8 + 1141682*x^9 + 16577*x^10) / (1 - x)^13.

a(n) = 13*a(n-1) - 78*a(n-2) + 286*a(n-3) - 715*a(n-4) + 1287*a(n-5) - 1716*a(n-6) + 1716*a(n-7) - 1287*a(n-8) + 715*a(n-9) - 286*a(n-10) + 78*a(n-11) - 13*a(n-12) + a(n-13) for n>13.

(End)

EXAMPLE

Some solutions for n=2:

..0....1....2....2....0....1....2....0....0....0....1....0....1....0....0....2

..2....1....2....0....2....2....0....2....2....2....0....2....0....0....2....2

..0....2....0....2....2....0....2....1....0....1....0....2....1....1....2....2

..2....2....0....2....1....0....2....2....2....2....1....2....2....1....0....1

..1....2....1....1....2....1....2....1....2....2....1....1....0....2....2....0

..2....2....1....2....2....1....0....0....2....2....1....0....2....2....1....0

..2....0....1....0....1....2....1....0....0....0....1....2....2....0....0....1

..2....1....1....2....2....2....2....2....1....0....0....2....2....0....2....2

..0....0....0....2....2....0....0....2....0....1....0....0....1....2....1....2

..0....1....0....0....0....0....1....2....1....1....2....1....2....1....0....2

..1....2....1....1....2....2....2....1....2....1....1....1....1....1....2....2

..1....2....1....2....2....1....0....2....2....1....1....0....2....1....2....1

CROSSREFS

Sequence in context: A074488 A059950 A198979 * A308156 A304397 A206593

Adjacent sequences:  A249964 A249965 A249966 * A249968 A249969 A249970

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 09 2014

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 20 16:50 EDT 2021. Contains 347586 sequences. (Running on oeis4.)