|
|
A052901
|
|
Periodic with period 3: a(3n)=3, a(3n+1)=a(3n+2)=2.
|
|
7
|
|
|
3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
G.f.: (2*x^2 + 2*x + 3)/(1-x^3).
a(n) = Sum((1/3)*(2*alpha^2 + 3*alpha + 2)*alpha^(-1-n), where alpha = RootOf(-1+x^3)).
a(n) = ceiling(7*(n+1)/3) - ceiling(7*n/3). - Tom Edgar, Jul 17 2014
a(n) = 12/(a(n-2)*a(n-1)).
|
|
MAPLE
|
spec := [S, {S=Union(Sequence(Z), Sequence(Z), Sequence(Prod(Z, Z, Z)))}, unlabeled]: seq(combstruct[count](spec, size=n), n=0..20);
|
|
MATHEMATICA
|
LinearRecurrence[{0, 0, 1}, {3, 2, 2}, 105] (* Ray Chandler, Aug 25 2015 *)
|
|
PROG
|
(Haskell)
a052901 n = a052901_list !! n
|
|
CROSSREFS
|
Cf. A176979 (decimal expansion of (15+sqrt(365))/10).
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
encyclopedia(AT)pommard.inria.fr, Jan 25 2000
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|