OFFSET
1,1
COMMENTS
Column 3 of A232515
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) +4*a(n-2) +a(n-3).
Empirical: G.f.: -16*x / ( (1+x)*(x^2+3*x-1) ), which means a(n) is 16 times 1, 2, 8, 25, 84, 276 and so on with pairs of adjacent numbers summing to A006190. - R. J. Mathar, Nov 23 2014
EXAMPLE
Some solutions for n=7
..0..1..2..1....0..1..0..1....0..1..0..1....0..1..0..1....2..1..0..1
..0..1..0..1....2..1..2..1....2..1..2..1....2..1..2..1....0..1..2..1
..2..1..2..1....2..1..2..1....2..1..2..1....0..1..0..1....2..1..0..1
..2..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1....2..1..2..1
..2..1..2..1....2..1..2..1....2..1..0..1....2..1..2..1....0..1..2..1
..0..1..0..1....0..1..0..1....0..1..2..1....0..1..2..1....0..1..0..1
..2..1..2..1....2..1..0..1....0..1..2..1....0..1..0..1....0..1..2..1
..0..1..0..1....2..1..2..1....2..1..0..1....0..1..2..1....0..1..0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 25 2013
STATUS
approved