OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = n^7 + 7*n^6 + 21*n^5 + 25*n^4 + 5*n^3 + 2*n^2 + 11*n - 8.
Conjectures from Colin Barker, Jan 26 2019: (Start)
G.f.: 2*x*(32 + 599*x + 1354*x^2 + 438*x^3 + 48*x^4 + 71*x^5 - 26*x^6 + 4*x^7) / (1 - x)^8.
a(n) = 8*a(n-1) - 28*a(n-2) + 56*a(n-3) - 70*a(n-4) + 56*a(n-5) - 28*a(n-6) + 8*a(n-7) - a(n-8) for n>8.
(End)
EXAMPLE
Some solutions for n=3:
..1. .1. .0. .0. .2. .0. .0. .2. .0. .1. .0. .1. .2. .0. .1. .2
..3. .1. .0. .1. .0. .3. .3. .0. .0. .0. .1. .2. .0. .3. .3. .2
..0. .0. .2. .2. .1. .1. .0. .1. .2. .2. .3. .3. .3. .3. .1. .2
..1. .3. .0. .0. .0. .3. .1. .0. .3. .3. .0. .1. .2. .0. .1. .1
..2. .0. .1. .0. .3. .2. .1. .2. .0. .2. .0. .0. .1. .0. .3. .3
..0. .2. .2. .2. .3. .0. .2. .2. .3. .2. .0. .0. .2. .3. .0. .3
..3. .3. .1. .2. .1. .3. .1. .1. .2. .2. .0. .2. .2. .3. .3. .2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 02 2016
STATUS
approved