OFFSET
0,2
FORMULA
a(n) = A329227(n+7) - 1.
Conjectures from Colin Barker, Nov 09 2019: (Start)
G.f.: (1 + x - x^2 + x^3 - x^4) / ((1 - x)*(1 - 2*x + x^2 - x^3)*(1 + x - x^3)).
a(n) = 2*a(n-1) - 2*a(n-4) + 2*a(n-5) - 2*a(n-6) + a(n-7) for n>6.
(End)
EXAMPLE
For n=3, a(3) = 1*1 + 1*2 + 1*2 + 2*3 = 11.
PROG
(Python)
p = lambda x:[1, 1, 1][x] if x<3 else p(x-2)+p(x-3)
a = lambda x:sum(p(i)*p(i+2) for i in range(x+1))
CROSSREFS
KEYWORD
nonn
AUTHOR
David Nacin, Nov 08 2019
STATUS
approved