OFFSET
0,2
COMMENTS
a(n)/a(n-1) tends to (9+sqrt(17))/2 = 6.56155281...
LINKS
FORMULA
G.f.: (1-5x)/(1-9x+16x^2). a(n)=Sum_{k, 0<=k<=n}A165253(n,k)*4^(n-k).
a(n) = ((17-sqrt(17))*(9+sqrt(17))^n+(17+sqrt(17))*(9-sqrt(17))^n )/(34*2^n). [From Klaus Brockhaus, Sep 26 2009]
MATHEMATICA
LinearRecurrence[{9, -16}, {1, 4}, 30] (* Harvey P. Dale, Feb 19 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Philippe Deléham, Sep 14 2009
STATUS
approved