OFFSET
1,2
LINKS
Colin Barker, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (0,6,0,-5).
FORMULA
a(n) = 6*a(n-2)-5*a(n-4).
MATHEMATICA
CoefficientList[Series[(1 + 5 x - 5 x^3)/(1 - 6 x^2 + 5 x^4), {x, 0, 30}], x] (* Vincenzo Librandi, Oct 23 2014 *)
PROG
(PARI) Vec((1+5*x-5*x^3)/(1-6*x^2+5*x^4) + O(x^100))
(PARI) a(n)=round((9-(-1)^n)*5^(n\2)/8) \\ Tani Akinari, Oct 26 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Colin Barker, Oct 23 2014
STATUS
approved