OFFSET
1,1
COMMENTS
Column 4 of A207024.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 6*n^3 + (27/2)*n^2 - (21/2)*n.
Conjectures from Colin Barker, Jun 17 2018: (Start)
G.f.: 9*x*(1 + 5*x - 2*x^2) / (1 - x)^4.
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n>4.
(End)
EXAMPLE
Some solutions for n=4:
1 1 1 1 1 0 0 1 1 1 0 0 1 0 1 0 1 0 0 1
1 1 1 1 0 1 0 0 1 1 0 0 1 0 1 0 1 1 0 0
1 1 0 1 0 1 0 0 0 1 0 0 1 0 1 0 1 1 0 0
0 1 0 1 0 1 0 0 0 1 0 0 1 0 1 0 1 1 0 0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 14 2012
STATUS
approved