A184053 Number of strings of n+2 numbers x(i) in -1..1 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, 3, 11, 21, 61, 179, 447, 1243, 3359, 9465, 25445, 70661, 201081, 558071, 1590047, 4493647, 12802275, 36449535, 103943735, 298249607, 853537659, 2455980115, 7066375759, 20376225441, 58856195841, 170131643499, 492840266543

Offset

1,2

Comments

Column 1 of A184061

Links

R. H. Hardin, Table of n, a(n) for n = 1..144

Example

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

Crossrefs

Sequence in context: A147191 A327607 A034185 * A240371 A158653 A129215

Adjacent sequences: A184050 A184051 A184052 * A184054 A184055 A184056

Keyword

nonn

Author

R. H. Hardin Jan 09 2011

Status

approved