OFFSET
1,1
COMMENTS
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (0, 2).
FORMULA
a(n) = (9-(-1)^n)*2^(1/4*(2*n-5+(-1)^n)).
G.f.: x*(5+8*x)/(1-2*x^2).
MATHEMATICA
LinearRecurrence[{0, 2}, {5, 8}, 60] (* Harvey P. Dale, Jul 20 2022 *)
PROG
(Magma) [ n le 2 select 2+3*n else 2*Self(n-2): n in [1..40] ];
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Klaus Brockhaus, Aug 21 2009
STATUS
approved