OFFSET
1,1
LINKS
Colin Barker, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (8,-24,32).
FORMULA
a(n) = ((2+2i)^n + (2-2i)^n + 4^n)/4. - Charles R Greathouse IV, Sep 15 2013
G.f.: -2*x*(12*x^2-6*x+1) / ((4*x-1)*(8*x^2-4*x+1)). - Colin Barker, Nov 10 2014
MATHEMATICA
Table[((2 + 2I)^n + (2 - 2I)^n + 4^n)/4, {n, 1, 30}]
PROG
(PARI) a(n)=((2+2*I)^n+(2-2*I)^n+4^n)/4 \\ Charles R Greathouse IV, Sep 15 2013
(PARI) Vec(-2*x*(12*x^2-6*x+1)/((4*x-1)*(8*x^2-4*x+1)) + O(x^100)) \\ Colin Barker, Nov 10 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
José María Grau Ribas, Sep 15 2013
EXTENSIONS
a(13)-a(25) from Charles R Greathouse IV, Sep 15 2013
STATUS
approved