OFFSET
1,2
COMMENTS
Column 4 of A183904.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..62
FORMULA
Empirical: a(n) = (1/24)*n^4 + (11/12)*n^3 + (179/24)*n^2 + (199/12)*n - 81 for n>3.
Conjectures from Colin Barker, Apr 05 2018: (Start)
G.f.: x*(1 + 51*x^2 - 116*x^3 + 74*x^4 - 2*x^5 - 5*x^6 - 2*x^7) / (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>8.
(End)
EXAMPLE
All solutions for n=2:
..0....0....0....0....0
..1....1....2....1....0
..3....2....3....1....0
..3....2....4....2....0
..4....4....4....3....0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 07 2011
STATUS
approved