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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A200166 Number of -n..n arrays x(0..2) of 3 elements with nonzero sum and with zero through 2 differences all nonzero. 1
2, 34, 128, 348, 726, 1326, 2180, 3352, 4874, 6810, 9192, 12084, 15518, 19558, 24236, 29616, 35730, 42642, 50384, 59020, 68582, 79134, 90708, 103368, 117146, 132106, 148280, 165732, 184494, 204630, 226172, 249184, 273698, 299778, 327456, 356796 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 3 of A200165.

LINKS

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

Index entries for linear recurrences with constant coefficients, signature (3, -2, -2, 3, -1).

FORMULA

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

Conjectures from Colin Barker, May 17 2018: (Start)

G.f.: 2*x*(1 + 14*x + 15*x^2 + 18*x^3) / ((1 - x)^4*(1 + x)).

a(n) = 11*n - 13*n^2 + 8*n^3 for n even.

a(n) = -4 + 11*n - 13*n^2 + 8*n^3 for n odd.

(End)

EXAMPLE

Some solutions for n=5:

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

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

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

MATHEMATICA

LinearRecurrence[{3, -2, -2, 3, -1}, {2, 34, 128, 348, 726}, 40] (* Harvey P. Dale, Feb 28 2012 *)

CROSSREFS

Cf. A200165.

Sequence in context: A067130 A263226 A200821 * A226407 A226336 A213826

Adjacent sequences:  A200163 A200164 A200165 * A200167 A200168 A200169

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 13 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 October 16 05:54 EDT 2019. Contains 328045 sequences. (Running on oeis4.)