A183937 Number of strings of n numbers x(i) in -2..2 with sums of x(i) and of x(i)*x(i+1) both zero

1, 1, 5, 15, 81, 237, 1015, 3891, 16171, 66237, 297003, 1304467, 5981617, 27407859, 126441771, 584452845, 2721978059, 12719931479, 59862174023, 282898499059, 1341705275365, 6380905008633, 30422523202843, 145340620435425

Offset

1,3

Comments

Column 2 of A183944

Links

R. H. Hardin, Table of n, a(n) for n = 1..81

Example

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

Crossrefs

Sequence in context: A220818 A064678 A088935 * A275971 A030487 A165470

Adjacent sequences: A183934 A183935 A183936 * A183938 A183939 A183940

Keyword

nonn

Author

R. H. Hardin Jan 08 2011

Status

approved