OFFSET
1,2
FORMULA
Conjectures (Start)
G.f.: x*(1 + 6*x^4 - 3*x^5) / (1 - x)^3.
a(n) = 6 - 7*n + 2*n^2 for n>3.
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>3.
(End)
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Colin Barker, Jan 31 2018
STATUS
approved