A184054 Number of strings of n+2 numbers x(i) in -2..2 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, 9, 31, 107, 501, 2339, 10303, 44523, 198695, 888601, 3941855, 18017983, 83483541, 389450325, 1838319253, 8707491533, 41316656737, 196349474191, 934444664373, 4453775875859, 21254863852755, 101613183769703, 486794625431383

Offset

1,2

Comments

Column 2 of A184061

Links

R. H. Hardin, Table of n, a(n) for n = 1..40

Example

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

Crossrefs

Sequence in context: A321598 A048374 A226274 * A140323 A160653 A189436

Adjacent sequences: A184051 A184052 A184053 * A184055 A184056 A184057

Keyword

nonn

Author

R. H. Hardin Jan 09 2011

Status

approved