|
|
A099517
|
|
A transform of (1-x)/(1-2x).
|
|
1
|
|
|
1, 1, 2, 3, 6, 10, 17, 27, 44, 71, 116, 188, 305, 493, 798, 1291, 2090, 3382, 5473, 8855, 14328, 23183, 37512, 60696, 98209, 158905, 257114, 416019, 673134, 1089154, 1762289, 2851443, 4613732, 7465175, 12078908, 19544084, 31622993, 51167077
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,3
|
|
COMMENTS
|
A transform of A011782 under the mapping g(x)->(1/(1+x^3))g(x/(1+x^3))
|
|
LINKS
|
|
|
FORMULA
|
G.f.: (1-x+x^3)/((1+x^3)*(1-2*x+x^3)).
a(n) = 2*a(n-1)-2*a(n-3)+2*a(n-4)-a(n-6).
a(n) = sum{k=0..floor(n/3), binomial(n-2*k, k)*(-1)^k*(2^(n-3*k)+0^(n-3*k))/2}.
|
|
CROSSREFS
|
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|