OFFSET
1,1
COMMENTS
Column 4 of A220751.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..38
FORMULA
Empirical: a(n) = 18*a(n-1) - 33*a(n-2) + 16*a(n-3) for n>8.
Conjectures from Colin Barker, Aug 03 2018: (Start)
G.f.: 2*x*(4 + 16*x + 437*x^2 + 1380*x^3 - 820*x^4 - 120*x^5 - 1187*x^6 + 560*x^7) / ((1 - x)^2*(1 - 16*x)).
a(n) = -312 + 16^n - 36*n for n>5.
(End)
EXAMPLE
Some solutions for n=3:
..0..1..1..1....0..0..1..0....0..1..0..1....1..0..0..0....1..0..0..1
..1..1..1..0....1..1..0..0....1..0..0..1....1..1..1..1....0..1..1..0
..1..0..0..0....1..0..0..1....0..1..0..1....1..0..0..1....1..0..1..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 18 2012
STATUS
approved