A199525 Number of -3..3 arrays x(0..n-1) of n elements with zero sum and no two consecutive zero elements

1, 6, 36, 212, 1324, 8342, 53302, 343710, 2232322, 14582218, 95702528, 630544704, 4168091856, 27630031358, 183604587444, 1222672695812, 8157398577024, 54515075729370, 364861668341252, 2445239266293460, 16407415704050100

Offset

1,2

Comments

Column 3 of A199530

Links

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

Example

Some solutions for n=5
..3...-2...-3...-1....0....1....3...-2....1....3...-2....0....1....2...-3....3
.-3....1....2....1....2....3....0....0...-3....3....0...-3...-3....1...-1...-2
..2....1...-3....0...-2...-1....1....2....0...-3...-1....1....2...-2....3....1
.-3....3....3....1...-2...-1...-3...-2...-1....0....3....2....1...-3...-2...-2
..1...-3....1...-1....2...-2...-1....2....3...-3....0....0...-1....2....3....0

Crossrefs

Sequence in context: A268454 A171280 A250348 * A074436 A036162 A061708

Adjacent sequences: A199522 A199523 A199524 * A199526 A199527 A199528

Keyword

nonn

Author

R. H. Hardin Nov 07 2011

Status

approved