login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A200205 Number of -n..n arrays x(0..3) of 4 elements with zero sum and nonzero second and third differences. 1
12, 68, 186, 422, 798, 1316, 2064, 3048, 4254, 5802, 7682, 9864, 12500, 15564, 19010, 23022, 27558, 32556, 38232, 44528, 51366, 58994, 67338, 76304, 86172, 96852, 108234, 120630, 133934, 148020, 163232, 179448, 196526, 214842, 234258, 254616 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 1 of A200204.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) -a(n-2) +2*a(n-3) -4*a(n-4) +2*a(n-5) -a(n-6) +2*a(n-7) -a(n-8).

Empirical g.f.: 2*x*(6 + 22*x + 31*x^2 + 47*x^3 + 26*x^4 + 9*x^5 + 3*x^6) / ((1 - x)^4*(1 + x + x^2)^2). - Colin Barker, May 20 2018

EXAMPLE

Some solutions for n=3:

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

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

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

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

CROSSREFS

Cf. A200204.

Sequence in context: A199415 A200204 A289384 * A059585 A213547 A050484

Adjacent sequences:  A200202 A200203 A200204 * A200206 A200207 A200208

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 14 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 24 03:38 EDT 2022. Contains 354005 sequences. (Running on oeis4.)