A184055 Number of strings of n+2 numbers x(i) in -3..3 with the sum of x(i) equal to zero and the sums of x(i)*x(i+1) and x(i)*x(i+2) equal to each other.

1, 11, 65, 243, 1731, 11251, 67083, 426379, 2719451, 17387313, 109704933, 710799097, 4675624993, 30453086763, 201255272997, 1329877798651, 8809229432607, 58426744937709, 388472975094601, 2592082676376493

Offset

1,2

Comments

Column 3 of A184061.

Links

Table of n, a(n) for n=1..20.

Example

Some solutions for n=4
.-2....1....1....0....3....3....3....0....1....1...-2...-3...-2....2...-2...-2
..0....2....0...-2....0...-2...-1...-1....0....2....2....0....1....1...-3....0
..0...-2...-2....0....0...-3....3....2....1...-1....1....0....0...-1....0....0
..0...-1....2....0...-3....3....0...-3...-1....1....0....0...-1....1....3....2
..2....2....0....2....0...-1...-3...-1...-1...-1...-2....0....1...-2...-1....0
..0...-2...-1....0....0....0...-2....3....0...-2....1....3....1...-1....3....0

Crossrefs

Cf. A184061.

Sequence in context: A250604 A233164 A215445 * A332750 A161459 A162288

Adjacent sequences: A184052 A184053 A184054 * A184056 A184057 A184058

Keyword

nonn

Author

R. H. Hardin, Jan 09 2011

Status

approved