OFFSET
1,1
COMMENTS
Seen on a quiz.
The recurrence was supplied by Zak Seidov, Dec 07 2009.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..200
Index entries for linear recurrences with constant coefficients, signature (6,8).
FORMULA
G.f.: 2*x*(-4 + 15*x)/(-1 + 6*x + 8*x^2). - V.J. Pohjola, Dec 07 2009
From Franck Maminirina Ramaharo, Nov 23 2018: (Start)
a(n) = ((77*sqrt(17) - 255)*(sqrt(17) + 3)^n - (77*sqrt(17) + 255)*(3 - sqrt(17))^n)/136.
E.g.f.: ((77*sqrt(17)*sinh(sqrt(17)*x) - 255*cosh(sqrt(17)*x))*exp(3*x) + 255)/68. (End)
MATHEMATICA
a[1] = 8; a[2] = 18; a[n_] := a[n] = 6*a[n - 1] + 8*a[n - 2]; Array[a, 20] (* Amiram Eldar, Nov 23 2018 *)
PROG
(Magma) I:=[8, 18]; [n le 2 select I[n] else 6*Self(n-1)+8*Self(n-2): n in [1..30]]; // Vincenzo Librandi, Nov 18 2011
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Anonymous, Dec 06 2009
EXTENSIONS
More terms from N. J. A. Sloane, Dec 07 2009
G.f. and name adapted to the offset by Bruno Berselli, Apr 04 2011
STATUS
approved