OFFSET
1,1
COMMENTS
Column 2 of A223933.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (1/10080)*n^8 + (1/504)*n^7 + (1/40)*n^6 + (109/720)*n^5 + (379/480)*n^4 + (317/144)*n^3 + (8027/2520)*n^2 + (691/420)*n + 1.
Conjectures from Colin Barker, Feb 21 2018: (Start)
G.f.: x*(9 - 27*x + 56*x^2 - 76*x^3 + 79*x^4 - 59*x^5 + 29*x^6 - 8*x^7 + x^8) / (1 - x)^9.
a(n) = 9*a(n-1) - 36*a(n-2) + 84*a(n-3) - 126*a(n-4) + 126*a(n-5) - 84*a(n-6) + 36*a(n-7) - 9*a(n-8) + a(n-9) for n>9.
(End)
EXAMPLE
Some solutions for n=3:
..2..1....0..0....1..1....1..0....0..0....0..0....1..2....0..0....2..1....0..2
..2..2....1..0....1..2....0..2....1..2....0..2....2..2....0..2....0..2....0..2
..1..2....2..2....2..1....0..1....0..1....1..0....2..2....0..0....0..0....0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 29 2013
STATUS
approved