OFFSET
0,2
FORMULA
Conjectures from Colin Barker, Feb 18 2016: (Start)
a(n) = -((-1)^n-2^(n+2)+3)*(n+2)/6 for n>0.
a(n) = 4*a(n-1)-2*a(n-2)-8*a(n-3)+7*a(n-4)+4*a(n-5)-4*a(n-6) for n>6.
G.f.: (1-x-2*x^2+7*x^3-7*x^4-4*x^5+4*x^6) / ((1-x)^2*(1+x)^2*(1-2*x)^2).
(End)
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved