OFFSET
1,4
COMMENTS
Column 1 of A279871.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 3*a(n-1) +3*a(n-2) -11*a(n-3) -6*a(n-4) +12*a(n-5) +8*a(n-6).
Conjectures from Colin Barker, Feb 26 2018: (Start)
G.f.: x^2*(1 - x)^3 / ((1 + x)^3*(1 - 2*x)^3).
a(n) = (3*2^n*n^2 + 96*n^2 + 21*2^n*n + 2^(n+4) - 16) / 648 for n even.
a(n) = (3*2^n*n^2 - 96*n^2 + 21*2^n*n + 2^(n+4) + 16) / 648 for n odd.
(End)
EXAMPLE
All solutions for n=4:
..0. .0. .0. .0. .0. .0
..1. .0. .1. .0. .1. .1
..1. .1. .0. .1. .1. .2
..0. .2. .0. .0. .2. .2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 21 2016
STATUS
approved