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!)
A201874 Number of zero-sum -n..n arrays of 3 elements with first and second differences also in -n..n. 2
3, 5, 15, 21, 27, 47, 57, 67, 97, 111, 125, 165, 183, 201, 251, 273, 295, 355, 381, 407, 477, 507, 537, 617, 651, 685, 775, 813, 851, 951, 993, 1035, 1145, 1191, 1237, 1357, 1407, 1457, 1587, 1641, 1695, 1835, 1893, 1951, 2101, 2163, 2225, 2385, 2451, 2517 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 3 of A201873.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

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

Empirical g.f.: x*(3 + 2*x + x^2)*(1 + 3*x^2 - 2*x^3 + x^4) / ((1 - x)^3*(1 + x + x^2)^2). - Colin Barker, Feb 15 2018

EXAMPLE

Some solutions for n=12:

.-2....8...-2...-9....2..-10....9....1....0...-5...-3....5...-6...11....3....2

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

.-1...-4....2....8....1....9...-9...-2....3....1....3...-3....6..-10...-7....0

CROSSREFS

Sequence in context: A063185 A208854 A165260 * A059528 A070079 A142717

Adjacent sequences: A201871 A201872 A201873 * A201875 A201876 A201877

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 06 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 February 4 19:58 EST 2023. Contains 360059 sequences. (Running on oeis4.)