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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A199707 Number of -n..n arrays x(0..4) of 5 elements with zero sum and no two neighbors equal. 1
14, 200, 892, 2734, 6504, 13324, 24394, 41344, 65788, 99858, 145596, 205612, 282386, 379036, 498440, 644218, 819692, 1028960, 1275766, 1564716, 1899968, 2286630, 2729288, 3233528, 3804374, 4447920, 5169588, 5975974, 6872944, 7867572, 8966146 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 5 of A199704.

LINKS

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

FORMULA

Empirical: a(n)=2*a(n-1)-a(n-3)-2*a(n-5)+2*a(n-6)+a(n-8)-2*a(n-10)+a(n-11).

Empirical g.f.: 2*x*(7 + 86*x + 246*x^2 + 482*x^3 + 618*x^4 + 618*x^5 + 426*x^6 + 222*x^7 + 47*x^8 + 8*x^9) / ((1 - x)^5*(1 + x)^2*(1 + x^2)*(1 + x + x^2)). - Colin Barker, May 16 2018

EXAMPLE

Some solutions for n=5:

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

..0....0....1...-3....1....3....1....2...-3...-2...-3...-2....0....2....3...-3

.-3...-4....2....3...-3....1...-4...-1...-1....5....1...-3...-3....4...-5....5

..3....2...-5....1...-4...-5....2....1...-3...-2....2....4....1...-4....4....1

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

CROSSREFS

Cf. A199704.

Sequence in context: A124239 A041366 A051817 * A222586 A221830 A068769

Adjacent sequences:  A199704 A199705 A199706 * A199708 A199709 A199710

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 09 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 July 21 00:39 EDT 2019. Contains 325189 sequences. (Running on oeis4.)