login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A199897 Number of -7..7 arrays x(0..n-1) of n elements with zero sum, and adjacent elements not both strictly positive and not both strictly negative 1
1, 15, 85, 799, 5839, 51395, 406575, 3500269, 28684325, 245319361, 2048301005, 17499467353, 147731409251, 1263413909311, 10741266363733, 92019265611439, 786112365529335, 6747253002120179, 57843127733658007, 497375672047480891 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 7 of A199898

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

EXAMPLE

Some solutions for n=6

..1....3....2...-6...-4...-2...-7....2...-7....2....5...-6...-3....6....5....0

..0...-4...-5....7....7....0....6...-4....1....0....0....1....0...-2....0....6

.-1....0....6...-4....0....0....0....7...-3....1...-1...-3....0....2...-7...-5

..2....0...-7....2...-1....4...-6...-3....6...-7....0....4....7...-1....2....0

.-3...-2....7...-2....5...-5....0....1...-4....5....2...-3...-7....0...-3...-1

..1....3...-3....3...-7....3....7...-3....7...-1...-6....7....3...-5....3....0

CROSSREFS

Sequence in context: A138322 A206170 A177882 * A302948 A230676 A232070

Adjacent sequences:  A199894 A199895 A199896 * A199898 A199899 A199900

KEYWORD

nonn

AUTHOR

R. H. Hardin Nov 11 2011

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 March 18 11:15 EDT 2019. Contains 321283 sequences. (Running on oeis4.)