A200455 Number of -n..n arrays x(0..2) of 3 elements with zero sum and nonzero first and second differences.

4, 10, 26, 44, 72, 102, 142, 184, 236, 290, 354, 420, 496, 574, 662, 752, 852, 954, 1066, 1180, 1304, 1430, 1566, 1704, 1852, 2002, 2162, 2324, 2496, 2670, 2854, 3040, 3236, 3434, 3642, 3852, 4072, 4294, 4526, 4760, 5004, 5250, 5506, 5764, 6032, 6302, 6582

Offset

1,1

Comments

Row 1 of A200454

Links

Table of n, a(n) for n=1..47.

Formula

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

Example

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

Crossrefs

Sequence in context: A335637 A255718 A001214 * A269064 A307415 A322060

Adjacent sequences: A200452 A200453 A200454 * A200456 A200457 A200458

Keyword

nonn

Author

R. H. Hardin, Nov 18 2011

Status

approved