OFFSET
1,2
COMMENTS
Column 4 of A183912.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..180
FORMULA
Empirical: a(n) = (1/24)*n^4 + (3/4)*n^3 + (119/24)*n^2 - (95/4)*n + 23 for n>1.
Conjectures from Colin Barker, Apr 05 2018: (Start)
G.f.: x*(1 - 3*x + 20*x^2 - 24*x^3 + 3*x^4 + 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
All solutions for n=2:
..0....1
..0....2
..0....3
..0....4
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 07 2011
STATUS
approved