OFFSET
0,7
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,1,2).
FORMULA
G.f.: 1/(1-x^5-2*x^6).
a(n) = a(n-5)+2*a(n-6) for n>5, a(0) = a(5) = 1, a(1) = a(2) = a(3) = a(4) = 0.
EXAMPLE
a(6) = 2:
._._._._._._. ._._._._._._.
| | | | | | |
| | | |___|___|___|
|_____|_____| | | |
| | | | | | |
|___|___|___| |_____|_____|
MAPLE
a:= n-> (Matrix(6, (i, j)-> `if`(i+1=j, 1,
`if`(i=6, [2, 1, 0$4][j], 0)))^n. <<1, [0$4][], 1>>)[1, 1]:
seq(a(n), n=0..70);
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Alois P. Heinz, Jun 05 2013
STATUS
approved