OFFSET
1,2
COMMENTS
Row 2 of A280398.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 3*a(n-1) +a(n-2) -7*a(n-3) +4*a(n-5).
Empirical g.f.: 2*x^2*(-1+2*x^2+3*x^3) / ( (x-1)*(1+x)^2*(2*x-1)^2 ). - R. J. Mathar, Jan 04 2017
Empirical: a(n) = 2^(n-1)*n/9 +2^(n-1)*47/27 +(-1)^n*2*n/9 -10*(-1)^n/27-2. - R. J. Mathar, Jan 04 2017
EXAMPLE
Some solutions for n=4
..0..0..0..0. .0..1..1..1. .0..0..1..0. .0..0..1..1. .0..0..0..0
..0..0..1..1. .1..1..1..1. .0..0..0..0. .0..1..1..2. .0..1..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 02 2017
STATUS
approved