OFFSET
0,2
COMMENTS
a(n)/a(n-1) tends to (17+sqrt(33))/2 = 11.3722813...
For n>=2, a(n) equals 8^n times the permanent of the (2n-2) X (2n-2) tridiagonal matrix with 1/sqrt(8)'s along the main diagonal, and 1's along the superdiagonal and the subdiagonal. [John M. Campbell, Jul 08 2011]
LINKS
FORMULA
G.f.: (1-9*x)/(1-17*x+64*x^2).
a(n) = Sum_{k=0..n} A165253(n,k)*8^(n-k).
a(n) = ((33-sqrt(33))*(17+sqrt(33))^n+(33+sqrt(33))*(17-sqrt(33))^n)/(66*2^n). [Klaus Brockhaus, Sep 28 2009]
MATHEMATICA
LinearRecurrence[{17, -64}, {1, 8}, 20] (* Harvey P. Dale, Jun 08 2018 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Philippe Deléham, Sep 14 2009
STATUS
approved