OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = n^4 + 4*n^3 + 3*n^2 + 2*n + 2 for n>1.
Conjectures from Colin Barker, Jan 26 2019: (Start)
G.f.: 2*x*(5 + 8*x - 3*x^2 + 5*x^3 - 4*x^4 + x^5) / (1 - x)^5.
a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>6.
(End)
EXAMPLE
Some solutions for n=3:
..1. .3. .2. .3. .2. .1. .3. .3. .2. .0. .2. .3. .3. .2. .2. .2
..3. .1. .1. .0. .0. .2. .2. .0. .1. .0. .2. .2. .2. .2. .1. .3
..0. .0. .3. .1. .2. .0. .2. .1. .2. .1. .0. .3. .1. .3. .3. .2
..2. .2. .0. .0. .2. .0. .1. .3. .2. .2. .2. .2. .0. .2. .3. .2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 03 2016
STATUS
approved