OFFSET
0,2
COMMENTS
a(n)/a(n-1) tends to 6.53112887... = (5 + sqrt(65))/2
LINKS
FORMULA
a(n), n>1 = 5*a(n-1) + 10*a(n-2), given a(0) = 1, a(1) = 15. [a(n), a(n+1)] = the 2 X 2 matrix [0,1; 10,5]^n * [1,15]
O.g.f.: (-1-10*x)/(-1+5*x+10*x^2). - R. J. Mathar, Mar 15 2008
EXAMPLE
a(5) = 24375 = 5*a(4) + 10*a(3) = 5*3725 + 10*575.
[a(3), a(4)] = [575,3725] = [0,1; 10,5]^3 * [1,15].
MATHEMATICA
LinearRecurrence[{5, 10}, {1, 15}, 30] (* Harvey P. Dale, Jan 28 2021 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Gary W. Adamson, Mar 14 2008
EXTENSIONS
Corrected and extended by R. J. Mathar, Mar 15 2008
STATUS
approved