OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..999
Index entries for linear recurrences with constant coefficients, signature (18, -79).
FORMULA
a(n) = ((1+2*sqrt(2))*(9+sqrt(2))^n + (1-2*sqrt(2))*(9-sqrt(2))^n)/2.
G.f.: (1-5*x)/(1-18*x+79*x^2).
E.g.f.: exp(9*x)*( cosh(sqrt(2)*x) + 2*sqrt(2)*sinh(sqrt(2)*x) ). - G. C. Greubel, Dec 21 2016
MATHEMATICA
LinearRecurrence[{18, -79}, {1, 13}, 50] (* G. C. Greubel, Dec 21 2016 *)
PROG
(Magma) [n le 2 select 12*n-11 else 18*Self(n-1)-79*Self(n-2): n in [1..18]];
(PARI) Vec((1-5*x)/(1-18*x+79*x^2) + O(x^50)) \\ G. C. Greubel, Dec 21 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Klaus Brockhaus, Jul 27 2009
STATUS
approved