A201868 Number of zero-sum -3..3 arrays of n elements with first and second differences also in -3..3

1, 3, 15, 45, 169, 643, 2509, 10129, 41031, 166337, 678169, 2772981, 11365437, 46717997, 192513137, 795049313, 3289962901, 13637608037, 56617168555, 235369429109, 979676940333, 4082222870535, 17027439214453, 71089263424863

Offset

1,2

Comments

Column 3 of A201873

Links

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

Example

Some solutions for n=9
.-3...-3...-1...-1....3...-2...-3...-3....1...-1...-2....3....1...-3...-1...-2
..0....0...-1...-1....2...-1...-1....0....1...-2...-1....1...-1...-1....1....0
..1....1....0....0...-1....1...-2....1....1....0...-2....0....0....0....1....1
..1...-1....2....2...-2....2....0....1....0....0...-1....0...-1....0....0....2
..1...-1....1....1...-2....3....0....3....0....1....0...-3....1...-1...-2....0
.-1....1...-1....1....0....1....1....2...-1....2....0...-3....0....1...-1....0
.-1....2...-1....0...-1...-2....2....0....0....1....0....0...-1....2....0....1
..0....2...-1...-1...-1...-2....1...-2...-1....0....3....0....1....2....0....0
..2...-1....2...-1....2....0....2...-2...-1...-1....3....2....0....0....2...-2

Crossrefs

Sequence in context: A030505 A301632 A074355 * A260021 A005560 A100747

Adjacent sequences: A201865 A201866 A201867 * A201869 A201870 A201871

Keyword

nonn

Author

R. H. Hardin Dec 06 2011

Status

approved