A199835 Number of -n..n arrays x(0..5) of 6 elements with zero sum and no two neighbors summing to zero

10, 426, 3556, 15708, 49302, 124982, 273728, 538968, 978690, 1667554, 2699004, 4187380, 6270030, 9109422, 12895256, 17846576, 24213882, 32281242, 42368404, 54832908, 70072198, 88525734, 110677104, 137056136, 168241010, 204860370

Offset

1,1

Comments

Row 4 of A199832

Links

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

Formula

Empirical: a(n) = n*(2*n+1)*(2*n-1)*(66*n^2-35*n+19)/15.

Empirical: G.f.: 2*x*(5+183*x+575*x^2+281*x^3+12*x^4) / (x-1)^6 . - R. J. Mathar, Aug 01 2014

Example

Some solutions for n=3
..0....2....3....2...-1...-3....0...-1....2...-1....1....0....0...-1....0...-2
.-1...-1....0....1...-1....2....2...-3....2....0....3....2...-1....3....3...-2
..2...-1....1...-3....3....3....0....1...-3....2...-2....1....2...-2...-1...-1
..1...-2...-3...-3...-2....1...-1....0....2....2....0...-2...-3....1....0....3
.-2....0...-2....2....0....0...-1....2...-1....0...-1...-2...-1...-2...-3....0
..0....2....1....1....1...-3....0....1...-2...-3...-1....1....3....1....1....2

Crossrefs

Sequence in context: A248553 A374229 A126154 * A350565 A001327 A288325

Adjacent sequences: A199832 A199833 A199834 * A199836 A199837 A199838

Keyword

nonn

Author

R. H. Hardin, Nov 11 2011

Status

approved